EXCEPT ZR2 & AT4X models BORLA® system has a Valve Simulator Fits Factory Split Rear Exit vehicles ONLY. Installation REQUIRES removal of Factory Valance Tips. True Dual design. Installation REQUIRES cutting the Original Equipment system. Add Adapter 60706 (Qty. of 2) for Crew Cab With Standard Bed (6' 7") 157" WB See below for product Features & Benefits