EXCEPT ZR2 AT4X models. Factory Split Rear Exit vehicles ONLY. This system features unique BORLA(r) carbon fiber tips with bright centers. Add Adapter 60706 for Crew Cab with Standard Bed (6' 7) 157 Wheelbase vehicles. Replace the small muffler behind the primary muffler in the BORLA(r) S - Type system with Polyphonic Harmonizer 60680 to attain the ATAK(r) sound level (louder than S - Type). Optional True Dual Cat - Back(tm) system available, see the Related Parts section. BORLA(r) Cat - Back(tm) and Axle - Back exhaust systems feature patented straight - through and multi - core technology designed to unleash hidden horsepower. Increased exhaust velocity adds power, driving excitement, fuel economy, and the distinctive BORLA(r) Sound of Power respected by motoring enthusiasts everywhere. Each system is 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. Ultra - smooth mandrel bends ensure maximum flow power, and precision computer numerical control (CNC) manufacturing ensures an accurate fit. Best of all, BORLA(r) 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.