PLEASE NOTE: Some B9.5 vehicles may be equipped with an updated valve motor. Vehicles with valve actuator P/N 8S0-133-246-D require adapter P/N EXH0712, the required adapter is available at no charge with proof of purchase. Introducing the APR Catback Exhaust System for the Audi B9 RS4 and RS5 The APR Catback Exhaust System for the Audi B9 RS4 and RS5 is a complete, high-performance exhaust solution that runs the entire length of the vehicle from the catalyst back. This system is engineered to boost performance, elevate sound, and enhance aesthetics with RS-style diamond black oval exhaust tips that are sure to make a statement. Crafted from premium materials and built with advanced manufacturing techniques, this system is designed to withstand harsh conditions and deliver lasting performance. Expect a bold, aggressive growl at wide-open throttle, along with an impressive gain of 9 horsepower and 15 FT-LBS of torque to all four wheels! Unmatched Design and Precision Engineering Unlike anything currently available, the APR system includes downpipes extending to the factory catalyst in the upper engine bay, making this a true full-system upgrade. We’ve minimized restrictions with smooth transitions, oversized piping, and straight-through mufflers and resonators. Constructed from mandrel-bent T304 stainless steel with a brushed finish and TIG welding throughout, this exhaust system is as durable as it is striking. Installation is hassle-free, thanks to precision-fit brackets, OEM-style slip clamps, and an included upgraded tunnel brace to accommodate the oversized piping. Inspired by RS Performance Like the RS4 and RS5, this system stays with the unique single oversized midpipe design. It utilizes dual 2.75” (70mm) downpipes and midpipes that merge through a cast Y-junction into a massive 3.5” (91mm) midpipe. The integrated Helmholtz resonator minimizes drone through a straight-through design with a sound-canceling port, ensuring no compromise in exhaust flow. The system splits again via another cast Y into two rear, valve-controlled mufflers with sound absorption technology. These valves are fully integrated with the OEM control system, adjusting automatically to enhance sound during aggressive driving while maintaining a quieter profile during cruising. Finally, exhaust gases exit through dual cast Y-junctions into a quad 2.5” (63.5mm) system, terminating via oversized 7.25”x5” RS-style exhaust tips. The tips feature a diamond black finish and a subtle APR logo for a refined touch. Experience the APR Difference Designed for enthusiasts seeking the perfect balance of power, sound, style, and quality, the APR Catback Exhaust System for the Audi B9 RS4 and RS5 is a testament to engineering excellence. With its performance-driven design and durable construction, this system not only transforms your driving experience but also ensures years of reliable performance.