Race Cop Cars
When in the options menu, type in "i carry a badge". This will make you be able to race cop cars.
Go to the option menu and type in "remote braking". This will make your cars horn freeze your opponent whenever it is activated.
Everything Unlocked (Cars,Tracks)
To unlock everything (cars and tracks) simplygoto the options menu and type
"i have the key" - spaces included.
For smaller cars, enter your name as "mjcim.rc"
on the high score screen.