At the main menu, select "Single Player", then choose "Time Trial" and enter a name to unlock the "Cheats" option at the main menu. Select the "Cheats" option, then enter one of the following codes to activate the corresponding cheat function.
Function
How to unlock
All bonuses plus "Ghost Mode" option
Enter "MARK" as a code.
View credits
Enter "BGM" as a code.
Eagle
Win dining room on 3 volts.
GT Sport Car
Finish first in the 3V and 6V class in championship mode.