The best way to lower the front, in order to keep the suspension geometry and ride quality the same, would be spindles. Using spindles will keep the amount of suspension travel the same between the control arm and bumpstops and keep everything aligned just as it was before lowering. Using keys will decrease suspension travel, then you'll have to have the truck realigned. Normally keys are good for a 1-2" drop, but more than that will start to limit your suspension travel and you'll bottom out on the bumpstops more often.
The rears just use coil springs, but going any lower than 3" will start to limit travel between the axle and frame mounted bumpstops to the point where it may become bouncy. You can make more room for the axle to move up and down by removing the bumpstop bracket and remounting the bumpstop w/o the bracket. As for the shocks, you can use new shorter shocks, or use relocation brackets to retain your factory shocks.
