What are you going to use the truck for? Not many on here fans of the 3" body, unless you really dont' want to trim, and need to run really large tires.
I personally woudl reccomend going to offroaddesign.com and ordering their full 4" lift kit, with 4" Tough Country ez ride springs in front, and a 4" shackle flip in the rear.
Their kit includes EVERYTHIGN you will need.
This will allow you to run 33, maybe 35's no trimming. Minor trimming for 35's maybe. Then, if you want to go bigger, add the body lift, and trim to fit whatever you want.