i already have the 4" skyjacker rear leaves and the stock blocks on my truck. right now the front sits about 3in lower than the back. i am replacing the bs Rough country front end lift with a skyjacker class II kit. what would equalize it out, the 4" or 6" Class II kit? also, is the only difference in 6" and 4" kits the coils or are the brackets different aswell? anything helps...