Okay, maybe I'm missing something here, but what I got in your post was that you were hitting the bump stops when going over speed bumps? Sounds to me like the spring pack may be worn out and isn't giving you the proper spring rate for the truck. If that's the case, deal with the springs first, shocks won't help until the springs are taken care of. If you want to get taller shackles or lift springs for 1-3" while you do it, go for it, but deal with the underlying issue first.

If you're talking about buffing the bottom of your rear pumpkin in a natural way, just ignore all this. <img src="/forums/images/graemlins/smile.gif" alt="" />

James