I have 4.5 rc lift with 32x11.5x15 on my 97 xj..i want to run d window rims but I'm confused about the offset...i know i need 3.75 backspacing but what's my offset pos or neg..and how much...in short what size wheels do i need..thx

http://www.gtsparkplugs.com/Offset-to-Backspace.html

Quick google search results in this. I have 15x8" wheels with 4" backspacing. They're listed as a -12mm offset wheel. I've had these wheels with 31s and 3" lift, 31s and 4.5", 33s and 4.5", 35s and 4.5" and 35s with 5.5".