You will need new, shorter u-bolts for the axle since the blocks won't be there for a spacer.
Also, the stock lift blocks are also the bump stop which would hit the rubber block on the frame rail. If you do any wheeling and/or get your truck airborne you should make some other bump stop config.
Other than those two things there should be no problems. It will definitely lower your truck the 2" and keep the rear closer to the front height. The truck will probably look funny 2" lower in the rear, they're already low enough, especially if you have a hitch receiver below the bumper like me and almost everyone else on here.