Zone Offroad - 19-23 Chevy/GMC 1500 4WD 2in Leveling Kit W/ Upper Control ArmsThis kit has not been test fitted on Silverado ZR2 or Sierra AT4X models at this time; While it's not necessary on all vehicles, some tire wheel combinations have tight clearance to the factory control arms. To resolve this Zone Offroad includes a pair of optional weld on steering stop extensions that can be installed on the lower control arm to limit steering slightly; Stock Wheel and Tires will require wheel spacers. (Tight to upper ball joint and