Do I need C/C plates?

HA! Every Mustang I've ever had need c/c plates, stock suspension or otherwise. If I were you I would go ahead and put them on. Every Mustang I get gets c/c plates put on it. I learned my lesson after having to buy tires for 3 cars once a year. They give so much adjustment that an alignment shop has no reason not to align it right so you don't wear out tires like a mofo!