probably the lower ball joints than but i would be surpised if it was your LCA bushings gone bad. PRG also carries their LCA bushing kit if you weren't aware?
PRG Products i was told the lower ball joints cannot be replaced but i've seen them sold separately i think from rockauto?
here's what i had to do to get my OEM LCA's off because one bolt on each side was seized and nothing would break it loose. i even took it to a shop and they couldn't break it! i couldn't replace my bolts with the SPC Cambolts because of this. so i took a sawzall to it!
the shackles don't lift the truck at all. they lower depending on which one's you get. i got the Crown Suspension shackles which is adjustable from 1-2". my truck sat pretty high due to the 4" block, Deaver C-30's so i was getting 6"+ in the rear as you can see here. the a$$ end sits up too high compared to the front:
installed the shackles set to 2" which brought it down too low:
so i had to go back and set them to just 1" and here's how she sits now:
