Highly do not recommend this. Staggered wheel sizes look fugly on Mustangs.
If I would have known I would of taken pictures of this today when I took off my replica's, and put the factory wheels back on as I changed the fronts first. When I put the replica's back on tomorrow I can take some pictures.
Well its the best I got, but it still shows you that the 17's show too much sidewall to match up well, as its way taller than the sidewall on the rear. IMO to look good on a powerful RWD car you need to have a little bit more sidewall on the rear. Look at a drag car for example it would look stupid(probably more than just look) to have a bigger sidewal on the front than in the rear.
Cant find the thread but there was a really good pic of 17 front 18 rear and it doesnt look that good. The car would have to be slammed with a nice rake in the rear in order for it to look good. Also saw 18 front 17 rear and it looks even worse