there is a very famous lift kit around off roaders, for mild jeeping:
Old MAn Emu (OME), 2" lift kit, HD (there are 2 versions, Medium or Hard, Hard will give you a little more lift and most prefer it). It's around 700 bucks, though.
This is for the non srt version, and it replaces all 4 coils and all 4 springs:
OME 2.0" lift kit WK/XK
check the rest of the products in these 2 pages in case you need A-arms, wheel spacers, coil or strut spacers (to give a little more lift), etc:
Grand Cherokee 2005-2010 (WK, WH)