Moving the axle to the top of the springs will also lower the back end about 5"....gonna look a bit weird unless you lower the front too..... How wide of a wheel and what tires are you running on the rear now??? What shocks do you have on the truck???

Don't know how much money you want to spend, but a posi, housing floaters, 32" ladder bars, good shocks, and soft compound tires work quite well on a pickup...