Casey, I don't think the shims are always necessary. I bought the 2 degree shims when i put the lift on. when i went to have it lined up, the guy at the alignment place said that they weren't necessary, he said that they were way to much of an adjustment. however, my explorer still had 0 degree shims in it. i did have to go to 1.25 degree shims, but the guy at the shop just traded me for the 0's i had, cause he wanted a set to test alignments with.
Hope this helps,
Terry L. Knotts