Compact series bonuses
Successfully complete the indicated task to unlock the corresponding car:

Assassin Compact: Get 15 Takedowns.
Compact Collector: Win the Gold medal at the Silver Lake Eliminator (type varies in each game).
Compact Cop: Win the bronze medal or higher at the Silver Lake or Airport T1 and T2 Pursuit.
Dominator Compact: Get 10,000 Burnout Points.
Gangster Legend: Win the gold medal at the Palma Bay Legend Face-Off.
Legend Compact: Win the gold medal at the Interstate Loop Legend Face-Off.
Tuned Compact: Win five gold medals.

Coupe series bonuses
Successfully complete the indicated task to unlock the corresponding car:

Assassin Coupe: Get 60 Takedowns.

Mirror tracks
Unlock all Legend Face-Off cars to unlock Mirror mode in Single Event mode.

Muscle series bonuses
Successfully complete the indicated task to unlock the corresponding car:

Assassin Muscle: Get 30 Takedowns.
Classic Legend: Win the gold medal at the Big Sure Shore Legend Face-Off.
Dominator Muscle: Get 25,000 Burnout points.
Legend J-Muscle: Win the gold medal at the Airport 1 and 2 Legend Face-Off.
Muscle Cop: Win the bronze medal at the Harbor Town or Sunrise Valley Pursuit.
Muscle Collector: Win the gold medal at the Harbor Town Eliminator (type varies in each game).
Tuned Muscle: Win twenty gold medals.

Sports car series bonuses
Successfully complete the indicated task to unlock the corresponding car:

Assassin Sports Car: Get 100 Takedowns.

Super car series bonuses
Successfully complete the indicated task to unlock the corresponding car:

Assassin Super Car : Get 150 Takedowns.

World Tour mode bonuses
Successfully complete the indicated task to unlock the corresponding car:

Cop Racer: Win a gold medal in all Pursuit events.
Firetruck: Win a gold medal in all Crash events.
Gangster Boss: Win a gold medal in all Race events.