I want to know what i'd need to fit 31's on a cherokee.. id like to do as cheaply as possible.. could i just trim the fenders or would i need to get blocks/spacers also

 

You can just trim but they would just barely fit. I'd spend the extra 150 bucks on a 2 inch spacer and 2 inch rear shackle so you have some flex room.

 

Trim your fenders (a lot) and you could actually fit 33's. Just depends on how much articulation you want. Look up Mike H's profile on here and you'll see he's running a 2.5" OME lift with 33's. Click on his photo albums and you'll see the kind of fender trimming it takes.

 

check out ebay found a 3in lift for $120. blocks in the front and add-leafs in the back.

 

I would go this route... and with add a leaf I would prolly go with like 1" block and it should sit level