Proving Ground, England Track
Enter the options menu, select CREDITS and then select DEVELOPERS. When the FMV clip finishes, hold R1 and enter Left, Circle, Up, Down, Right, Right and Right.
K.C. Monoxide Car (#101)
Do the same as above except enter L2 and Square, Circle, X, Down, Up, Right, Left.
Drive as Shorty Leung (#100)
Same as above and enter: Hold R2, Square, Circle, X, Up, Down, Left, Right.
Play as Jocko Michaels (#167)
Same as above and enter: L1 and press Square, Triangle, Square, Circle, Square, X.
Play as Asher Boldt (#153)
Same as above and enter: L2 and press Square, Circle, Triangle, X.
You must beat the Superspeedway Shootout on Veteran or Legend difficulty level.
You must beat a season on the Veteran difficulty level.
You must beat the Short Track Challenge to get the Black Box Classic car.
You must beat the Half Season to get the Black Box Exotic car.
EA Sports Car
You must beat the Road Course Challenge to get the EA Sports car.