APR 18-25 Audi S4/S5 (B9) Catback Exhaust System

The APR Catback Exhaust System for the Audi B9 S4 and S5 is a complete, high-performance exhaust solution that runs the entire length of the vehicle from the catalyst back. Inspired by the larger center-pipe design of the higher-output RS4 and RS5 models, this system is engineered to boost performance, elevate sound, and enhance aesthetics with customizable 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 10 horsepower and 12 FT-LBS of torque to all four wheels!

• Smooth transitions and straight-through components maximize performance by reducing restrictions.
• Removable quad 3.5” motorsport-style polished tips with APR logo; optional styles available.
• Complete catalyst-back system including downpipes, extending from the factory catalyst back.
• 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.
• 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.
• Strikes the perfect balance of power, sound, style, and quality for enthusiasts.
• Performance gains of 10 HP and 12 FT-LBS of torque delivered to all four wheels.
• Valve-controlled rear mufflers dynamically adjust sound based on driving style.
• Integrated Helmholtz resonator minimizes drone and enhances sound quality.
• Includes an upgraded tunnel brace to accommodate the larger piping.
• Fully emissions compliant for worry-free operation.

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