Secret Music Track
Press [Up], [Down], [Up], [Down], [A], [B], [X], [Y] at the Start Screen.
Unlock everything except hidden music
At the title screen press [Up], [Up], [Down], [Down], [Left], [Right], [Left], [Right], [B], [A], [B].
Infinite Nitro
Enter the "vroooom" code at the Cheats section.