Lift for \'04 GMC 2500 Anybody know a good lift for a '04 GMC 2500HD? Something mild to fit 33's. I'm going to use as a tow rig to pull a RV/dirt bikes (no my Blazer is not going to become a trailer queen /forums/images/graemlins/tongue.gif ) Do I have to go with a 4" lift? Will a 2.5" lift work? I would like something that avoids lift blocks for the back.