You should be able to run any diameter wheel you choose The diameter of the wheel is not the critical factor. The overall diameter of the tire, and the correct offset is the deciding factor.
I have used 17x7 with 4.5 backspace and a 245/45/17 tire. Check the front of the lower control arm with full turn, as a little clearancing with a grinder on the lower lip of the control arm is the only place I have noticed any interferance with big hoops.
I currently use 18x8 on the front with 4 3/4 backspace and 245/40/18 tire and it fits good too. If you get really low in the front, the fender lip can be rolled or flattened slightly.
Pat Fleischman
