I run 33's with stock 3.73 in my 05 w/2 inch lift. Have 108k original owner. Top out around 75 cruise at 70 in fifth. never use sixth. Pull loads, long trips, you name it. If you drive hard accelerate hard or wheel hard I don't think you should do it. If you drive easy no hard wheel by all means do it. Have blown out rear spider gears and my front axle u-joint is going out, all my suspension bushing are going. I blame spider gears and bushings on pulling heavy loads 1-2k every week. yea dont pull weight with these little tonkas.
I also have home made cold air intake, throttle body spacer, and a chip.