Mia and Tia are supporting characters in Cars and Cars Toons, and minor characters in Cars 2. They are red (to match Lightning McQueen) 1992 Mazda Miatas. They are Lightning McQueen's biggest fans.
The glamorous groupies cheer him on whenever they can. Straddling the fine line between very excitable and completely hysterical, the twins have been known to faint just seeing Lightning wink at them, and they regularly feature in Lightning's own daydreams.