I checked out that website. They've got some pretty good information there.
I found some info there on the lifts, mainly the 6" vs the 8" lift. The 8" lift would most likely need new drive shafts, and puts more stress on the frame than the 6" lift. Also found out that the 37's might stress out the truck some with heavy offroading, but I hardly ever do anything heavy, so that should be no problem. Anyhow, its looking like I'll be throwing on a 6" lift with 37" M/T's.