Replace the small muffler behind the primary muffler in the BORLA S - Type system with Polyphonic Harmonizer 60680 to attain the ATAK sound level (louder than S - Type). BORLA'S Polyphonic Harmonizer Technology utilizes patented units that contain pipes of different diameters and lengths to create multiple exhaust notes that harmonize to deliver a clean, rich, full - bodied sound to the BORLA mufflers. The mufflers then enhance this sound to the character and volume appropriate for our Touring, S - Type and ATAK systems. Built from premium T - 304 stainless steel, superior to T - 400 series (such as 409), to give you the absolute best in performance and durability. Ultra - smooth mandrel bends ensure maximum flow power, and precision computer numerical control (CNC) manufacturing ensures an accurate fit. Best of all, BORLA stands behind every Polyphonic Harmonizer with a Million - Mile Warranty. Just what you'd expect from the world's most experienced (and most winning) exhaust brand.