3" lift is fine for 31's. Your tires will stuff fine. The body boost is a Budget boost. Body boost is like a body lift. Uniframe vehicles cannot get a body lift. If you go higher like 5-6" you will run into more problems than they are worth. Save your money and run 3" with the 31's. Keep the saved money and buy long arms if you still want bigger. They will be worth the wait. Want 5"+? your looking at about 2-4 grand and you will still run into problems. You can cheap out on stuff but in the long run you will be unhappy. Im not a naysayer. I run 6.25" on short arms.
700 bucks for coils, shocks, brake lines
800 bucks for short arms
350 for trackbars
200 for misc things you fix after DW
Whatever you spend on tires and axles after that
150 for discos and rear endlinks
300 for addco antiswaybars because you will be swaying like a mofo
Now Ive spent more than that trying to make my jeep look nice, ride nice, and wheel nice. And it all started with 31" tires and a crappy 3.5" lift.
97 ZJ 5.9L 242/4.5" RE Coils/1.75" Spacers/Clayton arms/Addco's/RE brake lines/35x12.5 bfg muds/Currie steering/K&N/Claytons Front Drop tracbar/Dropped pitman/Bilstein 5125's/JKS BPE/JKS loop conversion/JKS Sliders/ZJilla rear bumper/Clayton front winch bumper/durango steering box/warn 9000i/Hambek Customs carbon fiber cowl hood #2of16/Hp30-8.8 4.56/ARB f+r