I asked some of the hardcore offroad folks in my area to give me some advice based on where I wanted to use the Hummer and ended up with a 4" Rancho.....then BFG 37s on powdercoated 17x10 ARs...handling is not altered at all. I used a Proflash Programmer after the mods and performance actually appears better via my "butt dyno"........
I still have decisions to make regarding exhaust, just running a Flowmaster at the moment but thinking JBA headers with a Banks exhaust.......
Good luck with your mods......I do 'em just for the fun of tinkering!!
Ed