Ok long story short. I bought a 2.5 ome medium lift and installed with 285 75 16s. Needless to say i want more lift and 35" tires. Is slee the only way to go for a 4" lift. My gosh the price of that kit haha. May be a dumb question( i have alot of those) but, what are "j springs"? Any help or advice will help more than youll ever know. Thanks