Blizzaks go on all four tires, that way the car can still make turns on snow and ice. I don't leave them on my car all year round, as the car drives like a tank with the Blizzaks, and I don't feel like wearing them down. If you get them through Firestone, take the optional package that they offer and they will switch your tire sets back and forth for you every winter/spring for free on your existing rims. The package is good for five years, but since this is my third winter with them, and I am a "valued customer" there, they really don't care how many years I keep coming back to have them switched for free. They'll also make sure that they and your summer's are rotated properly as well. They make Blizzaks to fit just about every rims size out there for just about every vehicle. Since the Mustang is alreay up in the air two times a year for the tires, I also end up getting an oil change, etc. as it is cheaper that way. Blizzaks aren't made to be pretty, just functional. The treads on them almost look like monster truck mudders with little tiny slits cut into each knobby. I still stand by them and think they are life saves! Like 98CC said, It's funny to pass 4X4's off in ditches as tool past them in a raging snow storm without any problems IN A MUSTANG! p.s. I'd take a pic of them, but I am WAY OVER my max allowed for posting pics on Stangnet (by about 750,000 bytes).