The Best BMW Z4 Performance Exhaust

A great soundtrack is a vital component of any performance vehicle. Where modern EV’s excite with instantaneous acceleration, they lack the staccato and crescendo achieved with an internal combustion engine. Whether it’s a throbbing V8 burble or shrieking 4-cylinder, a great aural note can enhance any and every drive.

Many performance vehicles come from the factory with exhaust systems that provide excellent sound and don’t restrict engine output. Most owners, however, are always looking for that little bit extra. That could be more performance thanks to a less restrictive exhaust setup, more noise or a finely tuned exhaust note.

The BMW Z4 is one of the better sounding vehicles to have been produced in recent years, whether it’s an early smooth inline-six or later brawny turbocharged model, the exhaust notes no doubt add to the driving pleasure. The systems below aim to enhance the sound, pumping up the volume and often releasing some extra airflow and a few horsepower in the process.

Exhaust Types

Back Box

The smallest, cheapest (mostly) method of getting more noise from any exhaust system. A back box (often referred to as a muffler), simply replaces the rear silencer and a small length of pipework, likely also including larger exhaust tips. These modifications allow increases in sound to enhance every drive, while some may also give small increases in power.

Thanks to their relatively small size they are generally one of the cheaper methods of extracting more sound from any vehicle, while their relative simplicity means parts can often be fit across many different engine variants of the same model.

Cat-back Exhaust

The natural progression from a back box upgrade is to change out the entire cat-back section of the exhaust. As the name implies, this type of upgrade changes the rear muffler and centre pipe up to the catalytic converter, found near the front of the exhaust. Here, larger diameter pipework can release extra airflow and allow for good increases in power, as well as giving much more sound, though this can be controlled with added resonators.

Expect to pay more for a cat-back system, when compared with a simple muffler change, but anticipate greater results. Fitment is also a little trickier, made increasingly difficult on older models thanks to worn exhaust hangers and the heavy OEM parts.

Things to Consider Before Purchasing

Catalytic Converters & Emissions

When performing exhaust modifications emissions can be negatively affected. This only applies however, when changing parts that contain the catalytic converter at the front end of the exhaust system or the GPF in more modern cars.

Thankfully, cat-back systems and back box upgrades, as shown below, do not generally affect the emissions regulations of the vehicle. This means no increase in emissions over what the car is producing before modifications or not enough to make the vehicle fail an MOT.

Bolt-on or Professional Installation

Many vehicles have performance exhaust upgrades that will simply bolt-on, replacing original components using standard flanges and gaskets for a simple and quick install.

Extra complication is caused when cutting and welding is required to fit exhaust parts. Many vehicles require exhaust parts to be cut, particularly when fitting back box-only upgrades. Attaching the new parts to the cut section of the OEM exhaust can sometimes be performed with sleeves or extension pipes that bolt/ clamp on however, in many cases this will require professional welding services to attach new parts to the vehicle.

Noise

While it may seem obvious that any exhaust upgrade will likely increase noise output, many owners are not aware of just how much this can affect driving the vehicle. Exhaust systems that lack resonators are much more likely to cause unwanted vibrations and droning, particularly at sustained high speeds on the motorway.

Excessive noise may also be detrimental for owners’ relationships with their neighbours and the local constabulary. It is recommended to have at least one resonator after the catalytic converter to dampen noise and keep the vehicle within legal and social limits.

The Best BMW Z4 E85 (2002-2005) Exhausts on the Market

Cat-Back Exhausts for E85 (2002-2005)

Gravity Cat-Back Exhaust System GV0488

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Since 2004 UK-based Gravity Performance have been designing, engineering and manufacturing specialist performance parts for a wide range of vehicles. Their products are suitable for vehicles used on both the road and the track, specifically aimed at providing maximum performance without the usual high-end brand price tags. Quality standards are high, maintained by using excellent construction materials and carefully monitoring production processes.

This free-flowing exhaust system allows the engine to sing freely, whilst also promising to release a little extra horsepower and give better throttle response. Torque and power should see an increase across the rev range thanks to the increased diameter and mandrel bent pipework.

Crafted from 304-grade stainless steel, this exhaust won’t suffer from corrosion, often caused by heavily salted UK roads in the winter. The exhaust is fully TIG welded for accurate fitment and excellent strength.

Part Number: GV0488
Fitment type: Bolt on
Exhaust diameter: 2×2” into 2.5” pipe, twin 3” exhaust tips
Exhaust material: Stainless steel

Pros:

• Specialist performance parts manufacturer
• High-quality exhaust system
• Increased power and torque outputs
• Stainless steel construction prevents corrosion

Cons:

• Brand doesn’t have huge cache in the aftermarket parts industry

Back Boxes for E85 (2002-2005)

Bastuck Rear Silencer BMWZ4-76T

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Bastuck are a German aftermarket parts manufacturer that take design and quality very seriously. Though not a large company, Bastuck have put serious investment into on-site production facilities and even their own test track to assess and design parts that give the best performance whilst also meeting strict European regulations. They provide over 40,000 different parts including OEM replacements for defunct brands such as Triumph and Austin Healey alongside their aftermarket performance exhaust offerings.

This rear silencer from Bastuck promises not only to improve the looks of the exhaust outlets but also enhance engine sound without excess vibrations or unwanted motorway droning.

Stainless steel construction promises excellent resistance to corrosion, commonly found on UK vehicle exhaust systems, whilst also giving lightweight construction and excellent strength.

Part Number: BMWZ4-76T
Fitment type: Clamps (2×51-55mm)
Exhaust diameter: 2×2” pipes into 2×3” exhaust tips
Exhaust material: Stainless steel

Pros:

• Parts rigorously engineered and tested
• Improves look of vehicles rear end
• Stainless steel construction
• Installs simply with only two clamps required

Cons:

• Most expensive backbox E85 exhaust featured

Ulter Sport Muffler 102-240/70RS

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Since their inception in 1986 Ulter Sport have been all about exhausts. Humble beginnings creating replacement OEM parts soon led to high-quality aftermarket systems as the business began to expand and reach new customers. Product lines continue to strengthen and expand thanks to satisfied customers from across all of Europe.

This backbox from Ulter Sport promises a nice bass sound, without unwanted vibrations and droning that can become present in un-resonated exhaust systems. Power and torque should also see an increase thanks to improved airflow.

Ulter promises easy fitment to the standard exhaust, with aluminized steel being used in part construction for lightweight and resistance against heat and corrosion.

Part Number: 102-240/70RS
Fitment type: Clamps (2×51-55mm)
Exhaust diameter: 2×2” pipes into 2x70mm exhaust tips
Exhaust material: Aluminium plated steel

Pros:

• Much less expensive when compared to Bastuck offering
• Produced by exhaust specialists
• Increase in sound without drone
• Lightweight and sturdy construction

Cons:

• Mild steel construction could lead to corrosion issues

The Best BMW Z4 E85/E86 (2006-2009) Exhausts on the Market

Cat-Back Exhausts for E85/86 (2006-2009)

Scorpion Exhausts Resonated Cat-Back SBM071

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Scorpion Exhausts are no strangers to high-quality exhaust systems, having been at the peak of the industry for over 25 years. Each of their exhausts is hand crafted to ensure superb welding quality, proper fitment and no degradation in part quality. Lifetime guarantees can be offered thanks to rigorous R&D, including use in many of their sponsored race teams and their own motorsport vehicles.

This comprehensive cat-back system promises a simple bolt-on installation for instant increases in power and torque across the rev range, thanks to unrestricted airflow. Noise will be increased but kept reasonable with the in-built resonator. The Daytona-style exhaust tips also give a neat finish to the rear-end of the vehicle.

Manufactured from 304-grade stainless steel to ensure longevity and handcrafted for great finish quality on every exhaust. The system also yields a useful weight saving over the standard OEM exhaust system.

Part Number: SBM071
Fitment type: Bolt-on
Exhaust diameter: 2×2” pipes, 2×3” exhaust tips
Exhaust material: Stainless steel

Pros:

• Highly regarded UK-based exhaust manufacturer
• Improves engine power and torque output
• 304-grade stainless steel used in construction
• Lifetime guarantee

Cons:

• Expensive for a cat-back exhaust system

Gravity Cat-Back Exhaust GV0506

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Since 2004 UK-based Gravity Performance have been designing, engineering and manufacturing specialist performance parts for a wide range of vehicles. Their products are suitable for vehicles used on both the road and the track, specifically aimed at providing maximum performance without the usual high-end brand price tags. Quality standards are high, maintained by using excellent construction materials and carefully monitoring production processes.

This free-flowing exhaust system allows the engine to sing freely, whilst also promising to release a little extra horsepower and give better throttle response. Torque and power should see an increase across the rev range thanks to the increased diameter and mandrel bent pipework.

Crafted from 304-grade stainless steel, this exhaust won’t suffer from corrosion, often caused by heavily salted UK roads in the winter. The exhaust is fully TIG welded for accurate fitment and excellent strength.

Part Number: GV0506
Fitment type: Bolt on
Exhaust diameter: 2×2.25” into 3” pipe, twin 2.5” exhaust tips
Exhaust material: Stainless steel

Pros:

• Specialist performance parts manufacturer
• High-quality exhaust system
• Increased power and torque outputs
• Stainless steel construction prevents corrosion

Cons:

• Brand doesn’t have huge cache in the aftermarket parts industry

The Best BMW Z4M (2006-2009) Exhausts on the Market

Back Boxes for Z4M (2006-2009)

Eisenmann Rear Silencers B5263.00835

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Eisenmann are an award-winning exhaust specialist, hailing from Germany. The brand has experience with OEM parts, aftermarket upgrades and even motorsport components. This has led to quality standards that are extremely high, culminating in durable and high-performing exhausts. The company has been working closely with manufacturers like Porsche for over 30 years, their experience clearly showing in the finished product.

Though expensive, these rear exhaust silencers for the Z4M promise a substantial increase in the noise from the fabulous straight six, without hideous drone on the motorway. Quality components are used to release more sound along with a little extra power from the engine. Sound levels can be chosen with either Sport (increase of 5db) or Race (increase of 9db) options, depending on the intended use.

All aftermarket systems from Eisenmann are made to order and hand crafted from high-quality stainless-steel components. All products come with Eisenmann’s two-year warranty but should last much longer, even against the harsh UK road conditions, thanks to high quality metals and production standards.

Part Number: B5263.00835
Fitment type: Clamped or welded
Exhaust diameter: 4x83mm exhaust tips
Exhaust material: Stainless steel

Pros:

• High quality exhaust components
• Created by an automotive exhaust specialist
• Increase in sound can be specified to suit the user
• May release a few extra horsepower from the engine

Cons:

• Expensive exhaust considering only the backboxes are included

The Best BMW Z4 E89 (2009-2016) Exhausts on the Market

Cat-Back Exhausts for E89 20i/28i Models

Gravity Cat-Back Exhaust GV1090

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Since 2004 UK-based Gravity Performance have been designing, engineering and manufacturing specialist performance parts for a wide range of vehicles. Their products are suitable for vehicles used on both the road and the track, specifically aimed at providing maximum performance without the usual high-end brand price tags. Quality standards are high, maintained by using excellent construction materials and carefully monitoring production processes.

This free-flowing exhaust system allows the engine to sing freely, whilst also promising to release a little extra horsepower and give better throttle response. Torque and power should see an increase across the rev range thanks to the increased diameter and mandrel bent pipework.

Crafted from 304-grade stainless steel, this exhaust won’t suffer from corrosion, often caused by heavily salted UK roads in the winter. The exhaust is fully TIG welded for accurate fitment and excellent strength.

Part Number: GV1090
Fitment type: Clamps
Exhaust diameter: 2.75” pipe, twin 3” exhaust tips
Exhaust material: Stainless steel

Pros:

• Specialist performance parts manufacturer
• High-quality exhaust system
• Increased power and torque outputs
• Stainless steel construction prevents corrosion

Cons:

• Brand doesn’t have huge cache in the aftermarket parts industry

Eisenmann Duplex Complete Cat-Back System B5434.00764

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Eisenmann are an award-winning exhaust specialist, hailing from Germany. The brand has experience with OEM parts, aftermarket upgrades and even motorsport components. This has led to quality standards that are extremely high, culminating in durable and high-performing exhausts. The company has been working closely with manufacturers like Porsche for over 30 years, their experience clearly showing in the finished product.

Though expensive, this exhaust system promises an increase in engine sound, without hideous drone on the motorway. Quality components are used to release a more sonorous engine note along with a little extra power from the engine. Sound levels can be chosen to suit the customer, with a Race option available, releasing extra sound for those that use their car on the weekends only or at the track.

All aftermarket systems from Eisenmann are made to order and hand crafted from high-quality stainless-steel components. All products come with Eisenmann’s two-year warranty but should last much longer, even against the harsh UK road conditions, thanks to high quality metals and production standards.

Part Number: B5434.00764
Fitment type: Bolt on
Exhaust diameter: 4×3” tailpipes
Exhaust material: Stainless steel

Pros:

• High quality exhaust components
• Created by an automotive exhaust specialist
• Increase in sound can be specified to suit the user
• Promises to release a few extra horsepower from the engine

Cons:

• Requires rear bumper modification to fit

Cat-Back Exhausts for E89 23i/30i Models

Eisenmann Duplex Complete Cat-Back System B5269.20764

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Eisenmann are an award-winning exhaust specialist, hailing from Germany. The brand has experience with OEM parts, aftermarket upgrades and even motorsport components. This has led to quality standards that are extremely high, culminating in durable and high-performing exhausts. The company has been working closely with manufacturers like Porsche for over 30 years, their experience clearly showing in the finished product.

Though expensive, this exhaust system promises an increase in engine sound, without hideous drone on the motorway. Quality components are used to release a more sonorous engine note along with a little extra power from the engine. Sound levels can be chosen to suit the customer, with a Race option available, releasing extra sound for those that use their car on the weekends only or at the track.

All aftermarket systems from Eisenmann are made to order and hand crafted from high-quality stainless-steel components. All products come with Eisenmann’s two-year warranty but should last much longer, even against the harsh UK road conditions, thanks to high quality metals and production standards.

Part Number: B5269.20764
Fitment type: Bolt on
Exhaust diameter: 4×3” tailpipes
Exhaust material: Stainless steel

Pros:

• High quality exhaust components
• Created by an automotive exhaust specialist
• Increase in sound can be specified to suit the user
• Promises to release a few extra horsepower from the engine

Cons:

• Requires rear bumper modification to fit

Back Box Exhausts for E89 23i/30i Models

Fox Sports Cat-Back Exhaust BM081002-290ANLR

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Another German brand, specialising in high-quality aftermarket exhaust components is Fox exhausts. Since the company was introduced in 1993, they have been producing some of the best and most sought-after components in the entire industry. All exhausts are crafted with 304-grade stainless steel and designed carefully to ensure accurate fitment and excellent longevity. This is backed by the manufacturers three-year, unlimited mileage warranty.

This backbox may be expensive for its size, but it’s made from high quality materials, likely meaning it will outlast the life of the car. As well as dressing up the rear of the car, this exhaust promises a subtle but noticeable increase in sound, giving enough extra noise for more driver enjoyment without annoying the neighbours. A small increase in power may also be found thanks to reduced restriction in exhaust airflow.

High quality stainless steel will help prevent corrosion, even in harsh UK winters. Quality and durability are backed by the unlimited mileage three-year warranty from Fox, in the case of any issues arising.

Part Number: BM081002-290ANLR
Fitment type: Clamps
Exhaust diameter: 2x55mm pipe, 2x80mm exhaust tips
Exhaust material: Stainless steel

Pros:

• High quality exhaust components
• Improves the look from the rear of the car
• Increase in sound without becoming antisocial
• Three-year, unlimited mileage warranty

Cons:

• High outlay for only one exhaust silencer

Cat-Back Exhausts for E89 35i Models

Friedrich Motorsport Duplex Cat-Back Exhaust System 881375AD-X

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Founded in 1992, Friedrich Motorsport have been specialising in engine and performance modifications for nearly 30 years. Their impressive growth, however, has seen the company decide to focus solely on aftermarket exhaust systems since 2005. This has allowed the brand to specialise and produce only the highest quality and best fitting components possible.

This cat-back exhaust system starts with larger diameter pipes, allowing extra flow and hence increasing engine output. A choice of exhaust tips will brighten up the look of the vehicles rear end, whilst also emitting more glorious engine sound.

Stainless steel in used in construction to ensure longevity, while parts are carefully crafted to ensure fitment and durability, even against the heavily salted UK roads.

Part Number: 881375AD-X
Fitment type: Clamps
Exhaust diameter: 2x70mm pipe, choice of exhaust tips
Exhaust material: Stainless steel

Pros:

• Designed and manufactured by leading exhaust specialists
• Larger diameter pipes allow for increase in engine horsepower
• Choice of exhaust tips
• Stainless steel construction promotes great durability

Cons:

• More expensive than Becker cat-back exhaust offering

Becker Cat-Back Exhaust BEXABH39

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The second of our Z4 E89 35i exhaust systems comes from Becker Performance. Another German exhaust specialist with a keen eye for high quality components, excellent durability and maximised performance. All their exhausts are designed to meet the demand of hardcore motorsport competition use and the harsh environments exhausts are subject to in such use. Manufacturing activities are kept in house to observe and maintain quality, a sure sign of the brands seriousness about making high-quality parts.

This exhaust system, installed after the catalytic convertors, will allow extra airflow and hence increase performance. Larger diameter pipes and less restriction will also give an increase in engine sound, releasing the six-cylinder note and enhancing every drive as a result. Mirror polished 3” tips finish the system to give a seriously purposeful look.

High quality, thick-gauge stainless steel is used for all components, giving confidence of longevity, even when subjected to thousands of heat cycles and harsh UK winter conditions.

Part Number: BEXABH39
Fitment type: Bolt on
Exhaust diameter: 2×2.5” pipe, 4×3” exhaust tips
Exhaust material: Stainless steel

Pros:

• More affordable than many premium rivals offerings
• Simple to install, bolt on system
• Releases extra power and performance
• High-quality materials and manufacturing methods used

Cons:

• Smaller diameter pipe than some rivals, may limit ultimate power

Back Box Exhausts for E89 35i Models

Friedrich Motorsport Duplex Sport Rear Silencer 861375D-X

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Founded in 1992, Friedrich Motorsport have been specialising in engine and performance modifications for nearly 30 years. Their impressive growth, however, has seen the company decide to focus solely on aftermarket exhaust systems since 2005. This has allowed the brand to specialise and produce only the highest quality and best fitting components possible.

This simple backbox exhaust system is designed solely for an increase in glorious engine sound. Less restrictive, larger diameter pipework and a re-worked silencer allows for an increase in volume but doesn’t lead to an antisocial or droning exhaust tone. Mirror finish exhaust tips, the size and shape chosen by the customer, helps finish off the purposeful look to the vehicles rear end.

Stainless steel in used in construction to ensure longevity, while parts are carefully crafted to ensure fitment and durability, even against the heavily salted UK roads.

Part Number: 861375D-X
Fitment type: Clamps
Exhaust diameter: 2x70mm pipe, choice of exhaust tips
Exhaust material: Stainless steel

Pros:

• High quality exhaust components
• Brand that specialises in performance exhausts
• Increase in engine noise, without unwanted droning
• Stainless steel used to prevent corrosion

Cons:

• High cost for a system that only changes backbox components

The Best BMW Z4 G29 (2018-Present) Exhausts on the Market

Back Box Exhausts for G29

Bastuck Duplex Sport Back Box Z4/G29-Q90RS

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Bastuck are a German aftermarket parts manufacturer that take design and quality very seriously. Though not a large company, Bastuck have put serious investment into on-site production facilities and even their own test track to assess and design parts that give the best performance whilst also meeting strict European regulations. They provide over 40,000 different parts including OEM replacements for defunct brands such as Triumph and Austin Healey alongside their aftermarket performance exhaust offerings.

This rear silencer from Bastuck promises not only to improve the looks of the exhaust outlets but also enhance engine sound without excess vibrations or unwanted motorway droning.

Stainless steel construction promises excellent resistance to corrosion, commonly found on UK vehicle exhaust systems, whilst also giving lightweight construction and excellent strength.

Part Number: Z4/G29-Q90RS
Fitment type: Clamps
Exhaust diameter: 2x70mm pipe, 4x90mm exhaust tips
Exhaust material: Stainless steel

Pros:

• Fits all G29 model BMW Z4’s
• Rigorously tested exhaust
• Increased size of exhaust tips dramatically changes rear end styling
• Stainless steel exhaust provides resistance to corrosion

Cons:

• Unlikely to see any performance gain

Cat-Back Exhausts for G29 M40i Models

Akrapovic Titanium Cat-Back Exhaust System S-BM/T/9H

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Akrapovic are arguably the kings of performance exhaust systems. This premium aftermarket brand has excelled in recent years, it’s extra high quality standards leading to their exhausts becoming approved upgrade items on multiple OEM vehicles. Their work with BMW is highly regarded thanks to excellent manufacturing standards, exotic materials and proven performance increases through installation of Akrapovic exhaust components.

This full system, installed just after the catalytic convertor, promises substantial increases in engine power output alongside the extra sound emitted. Larger diameter pipework allows for freer flowing of exhaust gasses, aided by mandrel bends and well-designed resonators. The exhaust rear section is made from titanium, with the exhaust tips made of carbon fibre. Not only do these exotic materials look excellent buy they also provide a substantial weight saving.

As with most premium aftermarket brands, Akrapovic is known to hold up on any warranty claims. The aforementioned exotic materials make for a durable product, one that won’t wilt and corrode, even in the harsh conditions of UK winters.

Part Number: S-BM/T/9H
Fitment type: Clamps
Exhaust diameter: Not stated
Exhaust material: Stainless steel, titanium & carbon fibre

Pros:

• Highly regarded exhaust manufacturer
• Gives a strong, powerful exhaust note
• Exotic materials used in construction
• Proven increases in engine performance

Cons:

• Seriously expensive exhaust system

Back Box Exhausts for G29 M40i Models

Friedrich Motorsport Duplex Back Box 861376TD-X

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Founded in 1992, Friedrich Motorsport have been specialising in engine and performance modifications for nearly 30 years. Their impressive growth, however, has seen the company decide to focus solely on aftermarket exhaust systems since 2005. This has allowed the brand to specialise and produce only the highest quality and best fitting components possible.

This simple backbox exhaust system is designed solely for an increase in glorious engine sound. Less restrictive, larger diameter pipework and a re-worked silencer allows for an increase in volume but doesn’t lead to an antisocial or droning exhaust tone. Mirror finish exhaust tips, the size and shape chosen by the customer, helps finish off the purposeful look to the vehicles rear end.

Stainless steel in used in construction to ensure longevity, while parts are carefully crafted to ensure fitment and durability, even against the heavily salted UK roads.

Part Number: 861376TD-X
Fitment type: Clamps
Exhaust diameter: 2x70mm pipe, choice of exhaust tips
Exhaust material: Stainless steel

Pros:

• High quality exhaust components
• Brand that specialises in performance exhausts
• Increase in engine noise, without unwanted droning
• Stainless steel used to prevent corrosion

Cons:

• High cost for a system that only changes backbox components

In Conclusion

Installing aftermarket exhaust parts could give your Z4 a whole new lease on life, reinvigorating your enjoyment of the car and bringing a smile to your face on every drive. We recommend avoiding overly loud systems, particularly if you often have early morning starts or use the vehicle for regular motorway driving.

Installation should be performed by qualified professionals if required, cheap link pipes often lead to leaks and could cause issues at your next MOT. Pick a quality system and install safely, then bask in the extra aural pleasures of your BMW sports car, get ready for every journey to be an event…

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