If you’re looking to really wake up your Audi B9 S4 or S5, the APR Catback Exhaust System is where it’s at. This isn’t just another exhaust; it’s a complete catalyst-back system that runs the full length of your ride, from the factory catalyst all the way back. It’s got that big center-pipe design inspired by the RS4 and RS5, which means you’re not just getting a new exhaust, you’re getting a performance upgrade that’s ready to unleash some serious power.

First off, let’s talk numbers. You can expect a solid boost of 10 horsepower and 12 FT-LBS of torque to all four wheels. That’s not just a marketing gimmick; you’ll feel the difference when you hit the gas. And the sound? It’s a bold, aggressive growl that’ll make you grin every time you start your engine. But don’t worry, it’s not all roar and no comfort. Thanks to the integrated Helmholtz resonator, you won’t have to deal with annoying drone while cruising.

APR has put a lot of thought into the design here. The system features dual 2.5" downpipes that transition into 2.75" midpipes, all merging through a cast Y-junction into a hefty 3.5" midpipe. This setup replaces the restrictive factory dual-pipe system, allowing for smoother flow and better performance. It's all made from T304 stainless steel with a brushed finish, so it’s not just tough but looks good too. The TIG welding throughout means it's built to last, even under harsh conditions.

Installation? Piece of cake. It comes with precision-fit brackets and OEM-style slip clamps, plus an upgraded tunnel brace to handle that oversized piping. You won’t need to be a mechanic to get this on your car, which is a huge plus. And let’s not forget about those polished 3.5" motorsport-style tips that finish off the look—subtle APR branding adds a nice touch without being over the top.

For those who love the thrill of driving, the valve-controlled rear mufflers are a game changer. They adjust automatically based on your driving style, giving you a louder, more aggressive sound when you’re in the mood for it, and a quieter profile when you’re just cruising. It’s the perfect blend of power, sound, and style, crafted for enthusiasts who appreciate quality.

So, if you’re ready to transform your driving experience and want an exhaust that delivers on both performance and aesthetics, the APR Catback Exhaust System is worth a serious look. It’s emissions compliant, so you can enjoy all that power without any worries. Trust me, once you hear that growl and feel the extra kick, you’ll wonder why you didn’t make the switch sooner.

• Complete catalyst-back system that includes downpipes, extending from the factory catalyst back.
• Performance gains of 10 HP and 12 FT-LBS of torque delivered to all four wheels.
• Premium T304 stainless steel construction with TIG welding for strength and durability.
• Optimized flow through dual 2.5" downpipes, 2.75" midpipes, and a 3.5" midpipe.
• Mandrel-bent brushed piping paired with electropolished cast splitters for a refined finish.
• Precision brackets and slip clamps ensure accurate alignment and hassle-free installation.
• Includes an upgraded tunnel brace to accommodate the larger piping.
• Integrated Helmholtz resonator minimizes drone and enhances sound quality.
• Valve-controlled rear mufflers dynamically adjust sound based on driving style.
• Removable quad 3.5" motorsport-style polished tips with APR logo; optional styles available.
• Smooth transitions and straight-through components maximize performance by reducing restrictions.
• Strikes the perfect balance of power, sound, style, and quality for enthusiasts.
• Fully emissions compliant for worry-free operation.

• Bending: Mandrel
• Brackets: Precise
• Brand: APR
• Clamp Style: Slip Clamp
• Clamps Included: Yes
• Exit Tube Diameter: 2.5"
• Material: T304 Stainless Steel
• Muffler Finish: Brushed
• Muffler Style: Sound Absorption, Helmholtz
• Tip Count: 4
• Tip Diameter: 3.5"
• Tip Finish: Polished Stainless Steel
• Tips Removable: Yes
• Tube Connection: Butt Joint
• Tube Diameter: 3.5"
• Tube Diameter: 2.75"
• Tube Diameter: 2.5"
• Tube Finish: Brushed
• Valve Actuation: OEM
• Valves: Yes
• Welding: TIG

Products Fitment:
Audi S4 2018-2025
Audi S5 2018-2024
Audi S5 Sportback 2018-2025