Even knowing the Audi S5 is more of a performance luxury car than it is a sports car Billy Boat Performance Exhaust wanted to offer something a little more for the true enthusiast. Like its little brother the Audi S5 Sport cat back exhaust is manufactured using only the highest grade T304 stainless steel materials available. CNC mandrel bent 2-1/2" tubing is used throughout the entire system for a smooth uninterrupted exhaust flow for added horsepower and torque. Hand fabricated mufflers incorporating B&B's unique Purge Resonance Technology (PRT) give the S5 a distinct exhaust note. The simple in design yet unique in theory PRT mufflers allows for a deep sporty note on hard acceleration but offer a mild tone while cruising without the unwanted interior resonance. By replacing the center muffler with a hand fabricated x-pipe we were able to give the S5 a little more exhaust note when tearing up the streets but still being able to maintain the lack of interior resonance at cruising speeds. To finish the system off B&B uses a quad tip design with 3.5" round double wall tips for a look that is pleasing to any enthusiast's eye.