Sooo, I threw a 22' from my Charger on the back of my Mustang.Yeah, a quick try shows they will fit on the back but in my opinion they are too big unless you can really bury them into the wheelwell. Even then, I think the car looks cartoonish or dare I say "donkish".
As for the front, unless you want to really sink the wheel into the wheelwell, in both ride height and track width, an 18" wheel will probably allow you a wider stance with way less clearance issues while turning. I would tend to agree that an 18" in the front would be optimal and personal taste would dictate if you choose to go 20" on the rear. Here are some pics.
Murstang :::::: Thanks for taking the time out of your day to mount those 22's... You are correct about the donk look. Not the look for a mustang. I guess 20x10rear and 18x8front is going to be the choice of purchase.. Hey MURSTANG since the 18x8 are smaller then your 20's on the front would i have to still lower the car to get the look of your mustang meaning how the front wheels look tucked.....