Nascar Thunder 2003 Cheats

If you want a drivers paint scheme that is locked complete a race in
veteran or legend mode and win, a new paint scheme will be awarded for
the driver you used.

Select the Thunder Challenge or Lightning Challenge at the game mode screen. Complete the various challenges to get new Thunder Plates. Note: The Plates are awarded randomly from game to game -- winning a certain track with a particular driver will not unlock the same Plate between games.

Unlock Dale Earnhardt:
Enter his name at the Create A Car screen to unlock Dale Earnhardt.
Unlock Fantasy Drivers:
Enter the name Extra Drivers as the name at the car creation screen to
unlock Fantasy Drivers.
Unlock Richard Petty:
Enter his name at the car creation screen to unlock Richard Petty.
Unlock Tiburon Track:
Insert a memory card that has another EA Sports save on it to unlock the
Tiburon Track.

To get new paint schemes and racetracks, you need to win a race on veteran or legend.

Use a driver with a paint scheme and win a race on veteran or legend to unlock a new paint scheme.