Debugmode
Go to the passwords and enter RABBITBADGER. 'Debugmode' will appear on the screen. Select this, and you will have access to all tracks and configurations of the cars.
Drive the last circuit
Go to the passwords and enter ENDGAMELEVEL.
To get 6 bonus tracks
Go to the passwords and enter BONUS.LEVELS.
To get all weapons
Go to the passwords and enter ALL.TOOLEDUP.