The APR CB100008 B5 S4 Stealth Exhaust is a stainless steel, mandrel bent, cat-back exhaust. The APR exhaust begins after the two lower factory catalytic converters and is two 2.25" pipes that merge into one 3" pipe. The APR CB100008 exhaust is very quiet and simply changes the tone of the exhaust to a deep, unobtrusive sound. With TIG welding, fully stainless construction, and CNC'ed hangers, you will not find a higher quality system on the market.

APR's Audi S4 cat-back exhaust is available with two different sound levels. The Stealth exhaust helps to maintain the S4's subdued character. While louder than stock, it is not loud enough to attract unwanted attention. The SRT exhaust replaces the center muffler with a special side resonator. This exhaust has a more aggressive sound and a distinctive note.