Best Aftermarket Exhaust Systems for Four-Cylinder Audis

Let’s face facts, here — most of us Audi enthusiasts have four-cylinder engines under our hoods. Most of the common enthusiast-driven Audis are the ones that just so happen to have four-cylinder engines. For instance, cars like the Audi A3, A4, A5 and TT all mostly have turbocharged four-pots under the hood. Even some S cars now have turbo-fours, like the S3 and TTS. While that’s not a bad thing, turbocharged four-cylinders naturally don’t sound very good from the factory, which makes most Audi enthusiasts search for aftermarket exhaust systems.


In fact, a new exhaust system is one of the first things most enthusiasts buy for their Audi. So we thought we’d offer up some advice on which exhaust systems to buy for your car because there seems to be a lot of enthusiasts who buy either cheap exhausts or the wrong exhaust and their cars often sound like crap.


So let’s take a look at the best ways to make your four-cylinder Audi sound better.





We’re big fans of Akrapovic, here at QD. The Slovenian-based company has been making the best exhaust systems on the planet for years now. In fact, Akrapovic is so good that some manufacturers actually use them to develop exhausts for road cars, race cars and motorcycles. Volkswagen even has an Akrapovic option for some of its models.

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However, their aftermarket systems are what we want to talk about. All of Akrapovic’s exhausts are made entirely in-house, as they have their own metal foundry on site. Their engineering, quality and attention to detail are second-to-none and their finished products are works of art.


More than that, though, they always sound the best. Akrapovic exhaust sound loud, clean and aggressive, without ever being too loud or too obnoxious.


The only downsides of Akrapovic exhausts are that they’re expensive and only offered on newer performance models. So the only four-cylinder Audis that you can buy a new Akrapovic system for are the Audi S3 and TTS.




Based in the UK, Milltek is one of our favorite exhaust options on the market for several reasons. One of which is the most important — they sound great. Despite the fact that four-cylinder engines inherently sound a bit flat, Milltek is able to make them sound truly special.


On every Audi I’ve heard with a Milltek exhaust, I’ve been impressed with the quality of the sound. Most exhaust companies just make four-cylinders sound loud, boomy and obnoxious. Not Milltek, though, as they often sound clean, natural and very aggressive. Adding a non-resonated Milltek exhaust to any Audi will make it sound truly special.


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Another reason why Milltek is one of our favorites is the fact that they offer exhaust options for an extensive list of Audis. Whereas Akrapovic only has systems for newer cars, Milltek offers systems for cars as old as the 1996 Audi A3 and has options for almost every Audi you can imagine. So regardless of whether or not your have a newer Audi or older one, you can likely get a Milltek system on your car.




Like Milltek, Supersprint offers exhaust systems for a wide variety of cars. However, Supersprint’s selection is probably more vast than any other exhaust maker’s. That’s because they save the tooling for every exhaust system they’ve ever made and can break one out to make an exhaust for virtually any car you can imagine.


Based in Italy, Supersprint has a massive yard filled with the tooling for its old exhaust systems. That offers high-quality exhaust systems to almost anyone with an Audi, which is incredibly helpful for older cars.


Downpipe or High-Flow Cat


Regardless of which exhaust system you choose for your car, it’s recommended that you also buy yourself a high-flow cat or catless downpipe to replace your stock catalytic converter. Reason being is that the stock cat is highly restrictive and not only drastically muffles your car’s exhaust note but also reduces power.

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Replacing your stock catalytic converter with one of the aforementioned options will not unlock unlock some horsepower but will also greatly improve your car’s sound.


Catless downpipes are usually cheaper, as they completely lack catalytic converters, but they also trip O2 sensors and cause Check Engine Lights (CEL), which can be annoying. Also, they can prevent your car from passing government emissions inspections in many parts of the world.


High-flow cats (HFC) are a bit more expensive but they do actually have catalytic converters in them. Depending on which HFC you choose, they can actually keep your O2 sensors from tripping, keeping your CEL off and they usually continue to allow your car to pass emissions inspection. They also unlock a ton of power and sound, though not as much as a true catless downpipe.


Upgrading your exhaust is one of the best ways to not only make your car more powerful but also more enjoyable to drive. They don’t unlock a ton of power but the extra sound they bring makes your car more exciting and more fun. That’s worth the expense.

CategoriesEditorial Tuning
Nico DeMattia

I've been in love with cars since I was a kid, specifically German cars. Now I get to drive them talk about them on the internet.