Re: 18s or 20s WK2 OEM Rims on WK
I was looking to do this too. A google search turned up several threads in Jeep Garage that turned me away from attempting it.
WK2 wheels have different offset than WK wheels. The wheel is moved in toward the suspension by about 1/2" and will interfere as you found out. You can use them but you need to use wheel spacers front & rear and longer wheel studs. Four spacers run about $300 plus cost of the wheels. Also, there are some threads about the lug nuts being different. The WK wheel lugs have a taper that holds the wheel. The WK2 lugs have a taper and a ridge that engages the wheel.
I felt the effort, cost and mods required to mount the WK2 wheels wasn't worth it. I'm going to go with STR reps when I get the cash together.
Randy- 2007 GC Limited 5.7L, Airaid Jr Intake Tube w/SynthaMax dry drop in filter, Challenger IAT sensor, JET 180 thermostat, SRT8 springs, Monroe Reflex struts/shocks, Addco front & rear anti-sway bars, 20x9 SRT8 Reps, BT catch can, Sonnax Line Pressure Booster, Molded splash guards, Partial debadge, Removed cross bars