Part #: 279S [Suburban, Yukon XL ROUGH COUNTRY LIFTS 6 inch kit 1500 4 wd.AVALANCHE , SUBURBAN , GMC YUKON XL. • Install Time: 8 - 10 hours• Wheel Backspacing: 4.5"• Recommended Tire Size: 35x12.50 gas engines only Will work with Auto Trac.• Increased ground clearance.• Designed to reuse factory compression travel stop Kit Contents:Front: Lifted knuckles, front & rear crossmembers, differential drop brackets, sway-bar links, lower skid plate, and CV spacers. Rear: Coils springs, track rod bracket, shock relocation brackets, brake line bracket, and bump stop brackets. Shocks: Kit includes (2) front Nitro 9000 shocks. One-piece, high clearance front crossmembers give plenty of ground clearance for improved off-road performance. New lifted knuckles maintain proper steering and ball joint angles Notes:• Fits 2000 - 2006 1500 models Only.• Frame bracket modification required.• If equipped with factory 17" wheels, then 17" orlarger aftermarket wheels must be used. • Torsion bar unloading tool required for installation.