Note: I am not sure if this has been posted (have not found it yet) ....so plz don't spit it back at me that it has been ....Thanks and have fun.

1)Take off the body
2)just loosen (as far as you want w/o removing the screw entirely) the screws that limit the travel distance for the suspension arm. Then use glue or a putty and applit to the remaining part of the screw that is thinner than the original portion.
3)shape it to the same witdth of the original so it can travel......If you really wanna go wild, just get a longer screw that is similar to that one and do the same...
3)put body back on(if done with modding your xmod....hopefully not:) )

Now you have lifted the truck chassis and not just the body... for more clearence you can do what others say with the shims for the body too...