When I lifted mine, I had 3.75" of lift in the rear with all stock components otherwise. Had no problems. The front was only at about 3"...but still had no problems. This is with stock control arms, sway bars, track bars, etc. You CAN use 3.5" springs and not buy anything else if you want.
However, if you could afford it, new track bars, shocks, etc. would be nice with that much lift. I think even a drop pitman arm for the steering would be nice on these. Adding that stuff will give you the full benefit of the lift.