Dave,
I have a 92 xlt w/33's, All I have is a 4" Trailmaster and I have no troubles with rubbing even at full bump. There are a lot of guys on here with the same set up, although a ot of guys seem to have a 3" body lift too. You can see what mine looks like on the Truck Haven trip photos, Colin Ignacio at the bottom, series of 6 pictures. I made all of the climbs that I've tried so far without gears or lockers, but they really do help out a lot. Plus I only get about 190 miles per tank without the gears, a little draining on the poor college student's pocket. Other things that will definitely be to your advantage off-road ar gears,(4.56's) to be closest to the stock ratio. I'm getting mine put in this week along with Detroit locker in the rear and a limited slip up front. I hope I was of some help to your decision and if not then I hope you're happy with whatever you choose to get.
Happy Wheelin'
Colin Ignacio
1992 XLT white