War's cherry red 1965 Mustang Fastback represents his red horse. It has Colorado plates - 971-Q4S
Ironically, Kripke originally was going to have the Winchesters drive a 1965 Mustang rather than an Impala:
"When I was originally writing the show I wanted to give the guys an American muscle car. My first choice was a '65 Mustang.
"My neighbour said it has to be a '67 Impala, because you can put a body in the trunk.
"He says, 'You want a car that, when people stop next to it at the lights, they lock their doors'.Source