Wheel fitment questions. Width and offset.

[TopElement]

Thanks for the input everyone.

I figure that if i'm getting new wheels, I might as well stuff the widest that will fit in there. Don't want to use 19's because of the extra weight, and increased chance of damaging an expensive wheel. Want to fill the wheelwells, but without having to do body work or rubbing the coilovers. With careful offset selection, 11" wheels may fit ok. Considering that my 3 sedans tuck 10.5's in the back, can't have the sports cars being outdone!
I went ahead and ordered a wheel width and offset measuring assembly. It bolts onto the hub, and allows me to try different width and offset possibilites. Tried to put the 19x13 wheels from the 360 in the rear wells, and the tires stuck out waaay too much. Definitely can't fit 355/25/19 back there!