ive heard zj front coils add about 1-1.5" lift while stiffening a bit and compensating for things like steel bumpers.. all that sounds good but what rear packs would you use to match the level? i'm assuming zj packs dont fit, do factory xj packs match? anyone done this before? blocks and shackles are out of the question b/c i need new packs back there anyway... how much lift would this give if any?