Cheat codes:

Unlimited Turbos:
     At the main menu press C-Right, Z, C-Up, C-Down, R, C-Left, Z, C-Right

Nightime Racing:
     At  the  main  menu  press  C-Up,  C-Up,  C-Down, C-Down, C-Left,
C-Right, C-Left, C-Right

Stealth Mode:
     At the main menu press C-Left, Z, Z, C-Up, C-Left, R, C-Down, C-Up

Wire frame Display:
     At  the main menu press C-Up, Z, C-Down, C-Left, C-Up, Z, C-Down,
C-Left

Mirrored Tracks:
     At the main menu press Z, R, Z, Z, R, Z, Z

Get TowJam Car:
     At the main menu press C-Up, C-Down, Z, R, C-Left, C-Right, C-Up,
C-Down

Bonus cars and tracks:
     Enter  "99T8DTY8VD  D7BDDDDDD2" as a password. Alternatively, win
the Hot Wheels Cup.

Additional bonus cars:
     Enter "9PTNPTFN6P NMQPPNPPPL" as a password.

All Cars and Tracks:
     When  you  start  the game go down to "sign in" then move over to
"password".  Then  for  all  cars  and  tracks  put  in  1  of these 3
passwords:

_WYVW2LVDW VTXWWVWWWF
_WYVVZCVDV VTXVVVVVVN
_WYZKZ1VDD OTX1TRGHSV

Mystery Cars:
     On  the  "Test  Track" when you get in the room with the three or
four  pillars(columns)  after  the  first one, there is a panel on the
right  wall,  that is discolored. Ram thrugh it and inside the tunnel,
is  a box shaped liked a car, that has ???'s all over it . Hit the box
head on, and you'll recieve a new car.