Replace the Polyphonic Harmonizer behind the primary muffler in the BORLA ATAK system with muffler 60679 to attain the S - Type sound level (quieter than ATAK). Built from premium T - 304 stainless steel, superior to T - 400 series knockoffs (such as 409), to give you the absolute best in performance and durability. Designed to provide maximum flow power. Precision computer numerical control (CNC) manufacturing ensures an accurate fit. Best of all, BORLA stands behind every direct fit muffler with a Million - Mile Warranty. Just what youd expect from the worlds most experienced (and most winning) exhaust brand.