Enter "CHECKERED FLAG" as a code under the "Cheat Codes" option to unlock all cars in Chase mode.
All fantasy drivers
Enter "RACE THE PACK" as a code under the "Cheat Codes" option to unlock all fantasy drivers.
Carl Edwards
Enter the name Carl EdwardsCar to unlock Carl Edwards.
Easy Gold in "Follow The Leader" challenge
Select the Gold (Hard) challenge for Follow The Leader. When the race starts, find the best spot to ram your car into the wall (head-on works best). You have to hit hard enough to destroy the suspension or you will get a "Failed" message, saying you hit the wall too much. If done correctly, you will pass the challenge.
Exient Cars
To unlock the Exient cars, insert "Exient Racing" (minus the quotes) in the cheat menu.
Wal-Mart car
Enter "WALMART EVERYDAY" as a code under the "Cheat Codes" option to unlock the Wal-Mart car.
Willis Hall
Enter your name as "Willis HallCar" (without the quotes) to unlock Willis Hall.