Last Updated on 20 February 2026 by Performance
One of the most common upgrades we see here at Demon Tweeks is the fitting of performance exhausts across all types of vehicles. Switching the original, factory-fitted exhaust system for an aftermarket, high-performance system can play a pivotal role in improving your car. From horsepower gains, to enhanced sound and weight savings, upgraded exhaust systems hold great benefits for lovers of speed, power and noise!
Built with over 50 years of experience and expertise, we’ve helped thousands of customers in not only fitting their new exhaust systems, but also helping them choose which one is best for them – and along the way we’ve been asked a lot of questions, like:
- What are the best brands when it comes to these performance exhausts?
- What are the overall benefits I will see?
- Why should I make this upgrade in the first place?
Here we’ve set out to answer some of the most common questions surrounding the wonderful world of performance exhausts, to help you understand the true performance benefits.
What is a performance exhaust and why do I want one?
Put in the simplest possible terms, a performance exhaust system replaces some or all of your car’s original exhaust system with improved pipework, silencers and finishing tips.
It will also have been designed for the original power output of the engine. It’s probably perfectly adequate for that power level, but once you start tuning the car it can become a limitation.
This means there’s two big areas for improvement for performance exhaust makers – sound and performance.
Sound
The sound is one of the biggest pull factors for some owners. A performance exhaust can transform the sound of a car. The combination of pipework and silencers mean each manufacturer can achieve their own trademark sound.
This is one of the biggest pull factors for some owners, and an upgraded exhaust can completely transform the sound of a car, changing the volume, pitch and tone. The specific combination of pipework and silencers mean each manufacturer can achieve their own trademark sound.
This can range from a sportier, more aggressive roar, through to a refined, high performance wail. Most manufacturers will have a consistent quality to their sound, however, a lot now offer a variety of different choices – many of them will offer similar exhausts, with and without resonators (a silencer designed to cut out certain frequencies of sound), or silencers.
Let’s face it, the big kid in all of us like nothing more than to hear the growl of car accelerating into the distance!
Performance
Ever wondered why some cars just sound powerful, and seem to have that extra kick? It’s not always about the engine size; often, it’s down to how efficiently those exhaust gases are getting out. A free flowing exhaust can help your car to generate more BHP and offer the aggressive tones we all know and love.
How quickly you can get the exhaust gasses out of the engine places a limit on how quickly you can get fresh air into the engine and thus how much power can be made. A better flowing exhaust always improves the power your engine can make. Performance exhausts achieve this in several ways; pipework diameter, exhaust layout, and reducing obstructions in the exhaust all play their part.
You will feel or hear some benefit from replacing any part of the exhaust system with performance parts, the benefits are most pronounced when you’re replacing the most restrictive parts of the original exhaust – which tends to be the catalytic converter and downpipe. When fitted alongside the correct software, you can get some serious power gains when you replace the original catalytic converter.
Are there different types of performance exhausts?
If you’ve done a bit of research on this already, you’ve probably heard or read a lot of different terms for types of exhaust. While this might sound complicated, the difference is simply how much of your original exhaust system you’re replacing. Let us explain:
Cat-back, GPF-back, and DPF-back exhausts
The cat-back system is often the go-to upgrade for a reason. It’s like the perfect middle ground, enough change to make a real difference without the need of replacing a catalytic converter, GPF or DPF .
When you buy a cat-back exhaust you generally get the middle pipework which sometimes includes a silencer (depending on the make and model you choose), and the rear pipework, silencers, and tailpipes. It’s all about maximising flow and minimising restrictions!
Now, if you’re driving a newer car with a Gasoline Particulate Filter (GPF) or a Diesel Particulate Filter (DPF), you’ll be looking at a GPF-back or DPF-back system. It’s a similar principle, but it connects behind the emissions hardware at the front of the exhaust.
A cat back exhaust is normally where you start seeing noticeable performance gains from an exhaust. You’re replacing enough of the pipework and silencers that the performance gains really start adding up. Exact figures will vary from car to car, so we cannot guarantee any exact power gain, but to give you some idea gains of around 10 BHP on the Fiesta ST180 are possible.
Turbo-Back exhausts
If you’re serious about power and don’t mind a bit of ECU tweaking, a turbo-back exhaust is where the real magic happens. We’re talking serious performance gains here.
As the name suggests, a turbo-back system replaces the entire exhaust from the turbocharger right back to the tailpipes. That means ditching the whole factory setup, including the original catalytic converter.
Now, you’ve got a choice: a high-flow sports cat or a straight-through de-cat pipe. Both will give you similar power boosts because modern sports cats are very efficient.
It is worth bearing in mind that when you get to the stage of replacing the catalytic converter, a remap is often essential. The ECU (Engine Control Unit) will be set-up to work with normal sensor readings from the factory cat. When you replace or remove it, these are going to change a lot. This can result in your car going into limp mode or the check-engine light coming on, the remap tells the ECU what range of readings to expect and prevents any of this unpleasantness.
If you want to go all-in and don’t mind remapping, then a turbo-back exhaust is a highly effective performance upgrade.
Downpipe
A downpipe is the section of exhaust connecting the turbo to the rest of the exhaust. If you’re fitting a turbo-back, you’re fitting a downpipe as part of that.
They are available as separate components too. If you’ve previously fitted a cat-back and now want to upgrade, that is an option on some cars, or you can also just fit a down-pipe with the rest of the exhaust staying stock. As the original cat is the biggest restriction, some people like to start there when upgrading.
Please note: Non type approved sports cats cannot legally be installed on a vehicle for use on public roads that were manufactured after 1/3/2001.
However, the gains won’t be as good as doing a full turbo-back exhaust. This is because the exhaust gas is going to be flowing from a bigger aftermarket pipework into the same old, narrower, factory exhaust.
This is normally where the Catalytic Converter/Gasoline Particulate Filter/Diesel Particulate Filter lives, so as we mentioned above, you’re probably going to have to run a remap to ensure your car runs correctly and takes advantage of the extra performance on offer.
What do Resonated and Non-Resonated mean?
If you enter your car details on our website whilst shopping for an exhaust, you may notice that you have a choice between resonated or non-resonated, or between exhausts with different numbers of silencers. This is the manufacturer giving you the option to fine-tune how the exhaust sounds.
A resonator is a special type of exhaust silencer designed to cut out specific sound frequencies. These are normally designed to quieten your exhaust down at idle and low engine speeds. The idea is that your exhaust is quiet and well-behaved during normal driving (on the motorway for example) but comes alive during “spirited” driving.
On some exhausts you can replace one of these with a straight through pipe. This will increase the noise your car makes, and make for a much more aggressive tone.
What difference does the width of an exhaust make?
You may notice that for some cars there are a range of different diameters of exhaust on offer.
If you have a non-turbo car, bigger isn’t always better. Going too wide can make the exhaust flow slower at low revs and lose you a bit of torque.
On a turbo-car, this isn’t really the case, and a bigger exhaust is usually going to support more power. How wide you need to go probably depends on your plans for the car. If you are leaving the engine untouched or going for modest bolt-on modifications, you will see power gains from any of the performance aftermarket systems we offer. If you have big plans in mind, going for a bigger exhaust when given the choice will help future-proof things a little.
What about cars with exhaust valves?
Increasingly if a car comes from the factory with electronically controlled valves in the exhaust system, you will have the option of aftermarket systems that accommodate these valves meaning you can enjoy both a better sounding aftermarket exhaust and the convenience of the adjustable exhaust sound.
Let’s take a look into some of the market leading Exhaust brands that are available here at Demon Tweeks –
Who are the best brands for performance exhausts?
Milltek
Big with the VAG scene, Milltek exhausts are popular for both the quality of their fit and finish, and for making very civilised sounding exhausts. The attention to detail and quality of engineering on offer here is genuinely outstanding. We’d describe the sound as being “refined performance car”.
Milltek are also big into new technology, offering exciting new developments like their “Active Sound” exhaust system which allows you to electronically tune the noise an exhaust makes. They are even developing exhausts for electric cars now!
Cobra Sport
Cobra exhausts have been making exhausts for five decades. Having started out with a wide range of performance exhausts for the Japanese market and models, from the likes of Nissan and Toyota, Cobra Sport focuses on performance, and their renowned quality has been winning them fans all over the car-tuning map as of late.
Scorpion
Scorpion exhausts are heavily involved in touring cars and top-flight motorcycle motorsports. They reckon this gives their signature sound a bit of a motorsport flavour and a focus on performance. They cover quite a range of popular performance cars covering off everything from brand new applications like the Hyundai i30N through to tuner favourites like the Golf GTi, BMW, Mercedes, and Ford ranges.
Remus
Remus Exhausts are from Austria. Another company with a long and proud motorsport heritage, Remus are well known for the aggressive growl of their exhausts. Perhaps this isn’t surprising given their previous partnership with the AMG DTM team. It doesn’t get much more aggressive or growly than DTM.
Akrapovic
Akrapovic make high quality exhausts for high end cars marques. With an application list that covers some seriously alluring machinery, Akrapovic offer exhausts that are made from the most expensive, lightweight materials including carbon fibre and titanium. This helps add the power and sound benefits without adding the extra weight. Akrapovic are without a doubt the go-to brand if money is no object.
Jetex
Jetex focus on making quiet exhausts. Their slogan is “Performance to blow your mind, not your ears.” To this end they carefully engineer their exhausts to be civilised and quiet at low RPMs. This means you’re not annoying your neighbours on cold starts or yourself on long drives. They are also Swedish which means their range takes in more Saabs and Volvos than many other companies.
Piper
Ever popular among owners of Vauxhall and Ford are Piper exhausts. With a rorty sound to match some hot hatches, Piper have long been the go-to choice if you like your car with a blue oval or griffin on the badge. They have some deep and enduring love for British motoring as well with an interesting range of retro exhausts for retro cars.
HKS
HKS have been around since 1973 and are huge in the world of Japanese tuning. You can be forgiven for not having heard of them if you are not into that scene, HKS offer a lot of axle-back type systems which come with the rear-most silencers and pipework. Because they are from Japan they cover some JDM applications which few or no western manufacturers cover.
What now?
Once you have decided which exhaust system suits you best, why not book in to our fitting centre to get your new parts professionally fitted. Found on the Wrexham Industrial Estate, you can also explore our Demon Tweeks showroom.
And if you want more inspiration and advice on what you want next for your vehicle, take an explore of our Demon Tweeks Blog!