You wont have to do anything with the rear. As for the front, you might have to bend over the pinch weld and remold the plastic inner fender well. I would install the spacers and see exactly where you have rubbing, if any, and then go from there. Here is a good write up on the pinch weld mod.
http://www.theultimatejeep.com/showt...ght=pinch+weld