I'm running the Firestone Destination A/T's in 305 with the same size rim as you, and the only little mod I had to make was cutting like 3" out of the inner part of the fender flare on the front bumper portion. The tire was rubbing when I turned, and I was afraid that the lugs would rip the bumper right off. In the pic below, the front-most edge of the tire would have been hitting the fender flare in the front.
You shouldn't need any more lift than you already have.