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.