Older Fords (and MoPars) have a 4 1/2 inch bolt circle, commomly called a "5 on 4 1/2". I couldn't tell you if they are the same on the newer Mustangs, but I suspect they are, since some guys are using wheel spacers to mount newer wheels on older cars. Looks kinda goofy to me, but to each his own...
Don't take it personally, I'm sure there's plenty of stuff on my car that doesn't appeal to everyone. Variety is what makes our cars interesting. If we all tried to make our cars look alike, we may as well restore them! How boring would that be? Ooops, now I've gone and pissed off the restorers, too!