In a lot of ways an aftermarket exhaust is the trademark of a modified car. Wheels are of course on of the biggest visual indicators but an exhaust is what makes you look up from whatever you’re doing so you can see what car is driving by. Furthermore you get more than a louder exhaust note, aftermarket cat-backs (and some axle-backs) can net you a decent amount of horsepower and torque, along with visually improving the back of your car.
AWE Exhaust for A4/S4
AWE is a great option for anyone who loves having tons of options. AWE makes three main versions of their exhaust: SwitchPath, Touring, and Track. The Track edition is their bare-bones no nonsense version. It features no resonators and no mufflers, you just get two pipes straight out the back which makes it the loudest of the three choices. Touring is the next tier exhaust and it has two resonators and two mufflers. This makes for a much quieter and more refined sound than the Track Edition for those who like attention but not too much. The SwitchPath is the top tier AWE exhaust for good reason. It combines features of both the Track and Touring and gives you the ability to switch between them with a remote controlled valve. In open valve mode it is about as loud as the Track Edition and with the valve closed it is in-between the Track and Touring in terms of volume. For every edition you also get the choice of four different exhaust tips styles (two colors and two sizes) so you can really go to town customizing this exhaust. The A4 has the same options of Switchback, Touring, and Track editions and the same variety of exhaust tips. Below are sound clips from each of the three editions for the B9 S4 so you can hear the differences between them all.
The Milltek Exhaust may not have the SwitchPath option of the AWE but they make up for it with excellent build quality and exhaust tone. For the S4 exhaust you get a choice between resonated and non-resonated versions as well as versions for vehicles equipped with the sport diff or the standard diff. Their A4 exhaust has options for resonated, half-resonated, and non-resonated. For exhaust tips each version gets about 5 choices in different colors, shapes, and finishes. You can check out the video below to hear what this exhaust sounds like on the S4.
Remus Exhaust for A4/S4
Remus is a staple in the Euro market so without a doubt they will be developing an exhaust for both the A4 and the S4. From Remus you can expect a great deal of research has gone into their development process so when their A4/S4 exhaust is released it will be among the best in terms of power gains and build quality. Check out the B8 S4 Remus Exhaust to give you an idea of their usual power gains and options.