View the Credits

Get to the Start screen. Hold L and R and press Up, B.

Unlock All Tracks

While at the Start Screen, hold L + R and press Up/Right, B.

Unlock All Cars

While at the start screen, hold L + R and press Up/Left, B.

Unlock High Speed Mode

Type in 2QjD +D1Q 9Fy2 5B0C as a password.

Unlock All Cars and Modes

Type in S/PD W1/H L8Q8 >VbB as a password.

Unlock All Tune-Ups

While at the Start Screen, hold L + R and press Down/Right, B.

Unlock Extra Modes

While at the Start Screen, hold L + R and press Right, B.  Then, hold L + R and press Left, B.