EXCEPT ZR2 & AT4X models. Factory Split Rear Exit Vehicles ONLY. Add Adapter 60706 for Crew Cab with Standard Bed (6' 7") 157" Wheelbase vehicles. This BORLA® system has a valve simulator to prevent the Check Engine Light from coming on. The 3.5" diameter into dual 2.75" system features BORLA®'s aggressive ATAK® muffler and Polyphonic Harmonizer Technology which 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 with no drone inside the vehicle. Replace the Polyphonic Harmonizer behind the muffler in this ATAK® system with muffler 60679 to attain the S-Type sound level (quieter than ATAK®). Tips NOT Included, reuse factory tips. Systems that include tips are also available. BORLA® Cat-Back™ & Axle-Back exhaust systems feature patented straight-through and multi-core technology to unleash hidden horsepower. 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 T-304 austenitic 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. Give your Silverado or Sierra the power and sound it deserves, bolt on a BORLA® Best of all, BORLA® 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.