I think the t-rex is overpriced IMO.
Although it might not be easy to get the correct valving and everything they worked so hard on for the shocks, and that billet mount (not really necessary IMO, steel could be used).
I really just don't like the fact they say "THIS IS NOT A LIFT KIT" , but they still raise the front end 2 or 2. 5", which anyone can see lift's the truck that amount.
ANyway on the kelderman I need air ride as my sj springs can't handle my truck and plow at the same time, not to mention if i go with a buckstop.
Although not really meant for off road, as long as the bags are somewhat protected, and you use limiting straps there shouldn't be too much of a problem, although an air bag suspension dosen't articulate well at all, unless you play with the bag pressures while articulating and have large bags with a good amount of travel.
I never said it was a good off road suspension though, just relating the big ass mounts they use on the higher lift kits, to the big ass spacers tough country uses.