Kinda left out the lift on the vehicle description.
88Racing, another moderator here, recommends Randy's Ring and Pinion. Give them a call and they'll probably be able to set you up. I've never had to deal with any shop for my truck so I dont know what it costs to have gears swapped out.
Randy's Ring & Pinion. The Differential Experts. Auto Parts & Services.
You could try looking for cams and other internal parts. Those have always shown improvements on gas engines.
Another form of boost that I'm actually considering (if it would just start raining money) is the squires turbo system. Might be worth looking into if you go off road a lot. Sometimes turbo lag can be a good thing out on the trail.