While many aftermarket exhaust systems for the Audi B8/B8.5 S4 deliver impressive sound when paired with factory catalytic converters, a common issue arises as those OEM cats begin to fail—often due to heat-related breakdown over time. As a result, many owners turn to catless test pipes, which unfortunately introduce excessive rasp, harshness, and unwanted exhaust tones when combined with most existing exhaust systems.
As the global leader in test pipe sales for the B8/B8.5 S4 3.0T, CAP recognized the need for a purpose-built solution. Since 2020, our team has been developing an exhaust system specifically engineered to work in harmony with catless test pipes. The focus was on eliminating unpleasant high-frequency tones and resonance, while maintaining optimal flow and performance.
The result is a cat-back exhaust system that delivers a deep, aggressive, and refined sound—even without catalytic converters. Real-world tested on over a dozen vehicles across varied driving conditions, this system reflects over four years of product development and refinement. For enthusiasts running catless setups, this is the most acoustically balanced and performance-driven exhaust solution available for the Audi B8/B8.5 S4 3.0T.
Introducing the CAP Catback Exhaust System – a complete post-catalytic exhaust solution for your Audi B8/B8.5 S4 3.0T. This is not just a rear section like other systems. Ours includes an integrated resonated downpipes, giving you the most exotic, best sounding exhaust on the market.
Designed to fit after the stock catalytic converters, this full system bolts up cleanly to:
It’s the perfect solution whether you’re running stock cats or test pipes.
CAP’s catback is more than just a rear muffler swap—it’s a full performance solution designed to maximize your 3.0T’s potential in both sound and flow and is the last exhaust system you’ll need.
***THIS IS A PRE-ORDER ITEM. LIMITED QUANTITIES WILL BE AVAILABLE APPROXIMATELY ON AUGUST 19, 2025***
Choose options