I've been told NOT to use any kind of wheel spacer on the mustangs. I wanted to use some for my mach 1, but did searching and searching, and all I came up with was people telling me not to use them, even the hubcentric ones.....so are they or are they not safe? If they are, then with the stock 17 x 9 tire/wheel, what would be a good size to go with for the mach?