The stock set up would fit 31" easily. With your set up (2.5" suspension and 3" body lifts), 32" shouldn't be a problem. To be sure, take it to a tire shop and have them mount a 32" on the front, put it under full compression, and turn the wheel side to side. You shouldn't have any problems with the rear. Most reputable tire shops will do it for free if you're going to buy a set from them.
Don't forget you may have to change your gear ratio to maintain the performance of the vehicle.
I'm pretty sure most people on this Board that run 32" or larger tires have low gear (4:10 or 4:56).