Right now i have ford keys and 2 inch spacers with 315 70 17 bfg ats. i want to put on bfg km2s 325 60 20 on a 10" wide wheel. Right now the only time i rub is backing off of my steep driveway when weight shifts from 1 side to the other it scrapes in the rear. i havnt done any trimming and there isnt much clearence between the control arm (i think) and the tire on the rear axel. the section width of my 315 is 11.8 on an 8.5" wheel, idk how wide my stock 03 z71 wheels are. the section width on the 325 is 13" on a 9.5" wheel. So my question is how much would a body lift help to keep it from rubbing and would i have to get wheel spacers so they dont rub on the control arms? Also how does the offset work?