05. Rancho developed its 4-inch kit to be used with 285/75R16 (32x11.50) tires on a 16x8 wheel with 41/2 inches of backspacing. If you want to run 35s with this kit (we wouldn't recommend it), you'll need to add a 3-inch body lift or trim a lot of the inner fenderwell and maybe even part of the front bumper. The GM wheel openings are not very accommodating of larger tires, so at the very minimum expect to trim the front air dam back 3/4-1 inch per side. This isn't a big deal and looks factory even to the trained eye.