If you need swap tires for the winter/summer, than I would keep one of the sets. It's much easier to simply swap the wheels rather than have to reinstall different tires twice a year. Plus, it will greatly lessen the chances for damaging the paint on your Mustang wheels if you don't have to change the rubber every 6 months.
Hatch Nation #13 : Rally Revolution #13 : ROTM Jan '13
It's Bryan, not Brian
RSVT-170 Build in Progress
Derusting Rusty Build in Progress