To unlock these cars, play Career Mode.

Car	How to unlock
Aperture X1	Get Least 3rd Or Higher On Aperture Science Cup.
Fruit Ninja	Get Least 3rd Or Higher On Fruit Ninja Cup.
Ledorean	Get Least 3rd Or Higher On Every Cup In Beginner Championship.
Roadster	Get Least 3rd Or HIgher On Every Cup In Master Championship.
Sleigh	Get Least 3rd Or Higher On Every Cup In Expert Championship.
TF2 Truck	Get Least 3rd Or Higher On Team Fortress Cup.
Touring	Get Least 3rd Or Higher On Every Cup In Intermidlate Championship.