Daria - Nathan's Wannabe '57 Ford Skyliner
In the episode "Life in the Past Lane" (#509), Nathan's retro-roadster looks like a standard 1957 2-door Ford Fairlane, until a later scene where he puts the top down. MTV's website identified the car as a 1957 Ford Skyliner. However, the rear roof pillar of Nathan's car is curved and not as thick as real Skyliners.
1957 Fairlane Club Victoria:
Real 1957 Ford Skyliners: