Just to chime in
I've got a 98 2wd with the shackles and TT, and I run 31" BFGs. There's a little rubbing ONLY when I have the wheel pinned on turns (like when I'm backing up), but I can only conjecture 32", at most, fitting under a TT 2" lift. Get the 3", and you'll be happy.
Cool, I used the word conjecture in a sentence.
Karl