Torsion keys won't do crap.....but they will do something for ya.....make you replace your ball joints often.
Axle shims are avaliable at probably any auto parts store.....or any 4x4 shop.
Good luck on fitting 38's on your 2wd edge(assuming that's what you got). Cuz I can't, and i've got 4" suspension, 3" body, 2" cranked bars, and 35's. Believe me...you'll need more lift in the front AND more in the rear.