Re: 2012 Sahara 18" on 2011 JGC Overland
18 inch Sahara wheels are working fine on my wk2 45mm vs 56mm offset for the stock wk2. The sahara wheels are moved outward 11mm but there is no rubbing on any setting with the stock Duelers and the full size spare fits in the compartment fine without the plastic bins.
Only thing I had to do other than bolt them on was pick up the sensors off of ebay as suggested earlier in the thread. I had the TPMS installed by the tire center at Sams Club for $5 per wheel.