Cars cheats and codes:
Cars Cheats
Bonus music track:Press Up, Down, Up, Down, A, B, X, Y when "Press Start" appears at the title screen.
Bonus music track:Press Up, Down, Up, Down, A, B, X, Y when "Press Start" appears at the title screen.
All cars:Press Up(2), Down(2), Left, Right, Left, Right, B, A, B when "Press Start" appears at the title screen.
Pistons Cup: Shortcut:When about to finish the last lap, jump just before the finish line. That will lead you to the finish.
from: http://www.consolecheatscodes.com