Ok this Yukon needs all kinds of help!!!
@HerbieHancock alright dude lets get this started down the right path. It appears to be the Rancho 4" might be wrong but pretty certain. Being a SLT with factory tow hitch I'm assuming its 3.73 gears which is plenty for 33s. Here is the list of things that need to be done.
1. Ditch the wheels, flares, tube steps, body moldings, z71 stickers, Yukon and slt badges, and take off that 3" body lift
2. Get either 20x10 or 20x12 on 33x12.50R20 or 305/55R20
3. Add 1.5" body lift to clear tires if needed plus 1" rear coil spacer and crank up keys some to level with rear
4. New tail lights, headlights, corner lights, fog lights
5. Detail entire car with compound buff, polish, wax