Here's my view on the body lift. When you put in the pucks, it raises the radiator so you have to mod the shroud or lower the radiator. The rear brake line gets to be a little short. Your shifter is now shorter. Your 4x4 shifter boot needs to get modified. So if your doing a body lift, do a body lift. Either go for a worthwhile two inches, or dont go through all that bs for nothing. (I have 2inches and an satisfied with it)

So if your getting 31s, your adding 1.5 in tire height, so no need to add more than 2inches lift. I have 4 inches lift with 33s, aka 2.5 inches more in tire height, and it looks natural, if not almost needing 35s.

I don't recommend extended shackles. They mess with your departure angle. They also make the car less stable, kind of like walking in heals. Add a leaf is so much better, I think. Plus while your in there, change the leaf springs bushings as they wear out and most of these trucks end up with cracked leaf eyelets. Check yours if anything.