That's the real question, How high do you want to go? What size tires are you trying to clear? I think body lifts suck, but that's just me. Stock YJ springs are flat from the factory. I wouldn't combine the two, the RE 2.5" springs will lift your YJ higher with stock shackles than you are now. No CV joint or SYE required with the RE kit w/0" shackles. If you combine the two, you may need SYE, CV drive shaft, transfer case drop and a drop pitman arm. At that point, just buy the RE5515 4" kit. Buy 0" shackles, SYE kit and have a CV drive shaft built. One clears 31X10.50 tires, the other clears 33X12.50 tires. What do you want?