Audi S4 Borla Products 

Borla Cat-Back exhausts 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 by motoring enthusiasts everywhere. Each system is built from premium Aircraft-Quality T-304 Stainless Steel, an alloy superior to T-400 series knockoffs, to give you the absolute best in performance and durability. Ultra-smooth mandrel bends ensure maximum flow and power, and precision computer-controlled CNC manufacturing ensures an accurate fit. Best of all, BORLA stands behind every system with a Million-Mile Warranty. Just what you'd expect from the world's most experienced (and most winning) exhaust brand.