Borla S-Type Cat-Back Exhaust System Focus STBorla S Type Cat Back Exhaust Systems Borla S type cat back exhaust systems feature patented straight through and multi core technology to unleash hidden horsepower and produce a more aggressive sound and higher flow. 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 300 Series austenitic stainless steel,