Appropriate Wheel Offset for 18" Wheels?

And now we've come full circle, http://www.ebay.com/itm/XXR-526-18x..._Car_Truck_Wheels&hash=item4d273d3ac3&vxp=mtr
a spacer on the rear, WHO FREAKIN CARES, the rear studs are about a 20 minute swap to 3" AND you can rotate the tires front to back. But go ahead and keep on with your search......