I'm looking into running some 13' gt500 waffle wheels on my 04' thinking of going 18x9 up front and 18x10 in the rear. Curious on how it would look on my red fire vert.
Offset won't be good (inward). To have a decent look and no rubbing at the inside you will have to run spacer for sure. Later gen of mustang have a higher wheel offset, new edge: ET20-30, S-197: ET40-45.