DML FAQ : Chassis : Do I have to change shocks with a 2-inch drop?
Your stock shocks will work just fine on a two inch drop, but if you go more, than you need to use special application drop shocks.
Up front, yes. I'm running Pro Comp Toxic Shocks up front, they cover a 0-3" drop and were only $29/each from Summit. Out back, don't bother. Also, use a hacksaw blade and shave an inch off the lower A frame bumpstops. Again, you don't have to touch the back ones.