Enter "Extra" as a first name and "Drivers" as a last name under the "Create-A-Car" option.
Enter "Dale" as a first name and "Earnhardt" as a last name under the "Create-A-Car" option.
Use a memory card with a saved file from an EA Sports 2003 game.
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.