Biker Mice From Mars

$30,000: 
Enter _, Square, _, X as a password, where "_" represents a space. 
Super hard difficulty level: 
Press Up, X, Left, Y, Down, B, Right, A, Up, X on controller two at 
the main menu. A laugh will confirm correct code entry. Select main 
race or battle mode to display the new difficulty option. 
Passwords: 
_, Triangle, Square, _ 
X, Square, _, Circle 
Square, Diamond, Diamond, V