i have a 1998 jeep cherokee sport and i want to higher it a little so i can fit 31" tires, but i dont want to buy a suspension lift i was just wondering what all will i need to lift my jeep 3" with spacers, i thought i found them on ebay but then i read something like i need back blocks to or something like that because spacers are only for the front????






Go with the 2" Daystar spacer/shackle lift. With a small amount of fender trimming you should be able to run 31" tires.
Also check out http://www.naxja.org They will have all of your Cherokee answers.
You only get 2.5" with spacers 3′ a lie and the rear will leave you leavel at best but add a leafs are around . Try the junk yard for longer springs and add only one leaf to rear. Going over 3′ changes stearing ride 4′ may need shocks and aliment.