Unlock Castrol SYNTEC Ford GT:

Enter the following code at the start screen:

D-pad Left, D-pad Right, D-pad Left, D-pad Right, D-pad Up, D-pad Down, D-pad Up, D-pad Down

Unlock Burger King Challenge:

Enter the following code at the start screen:

D-pad Up, D-pad Down, D-pad Up, D-pad Down, D-pad Left, D-pad Right, D-pad Left, D-pad Right

More Need for Speed Cheats
All "button press" cheats are courtesy of CVG