Borla 13-15 Audi S3 S-Type Dual Round Rolled Catback ExhaustBorla Cat Back and Rear Section exhaust systems feature patented straight through and multi core technology to unleash hidden horsepower. Increased exhaust velocity adds power; driving excitement; fuel economy; and the distinctive Borla Sound of power respected enthusiasts everywhere. Each system is built from premium 300 series austenitic stainless steel; superior to T 400 series knockoffs; to give you the absolute best in performance and durability.