S.C.A.R.S.

Crystal cup:
Enter LGSSSX as a password.

Diamond cup:
Enter CRKKYY as a password.

Zenith cup:
Enter DZPKKK as a password.

Master mode and all bonus cars:
Enter PXPRTS as a password.

Scorpion car:
Enter SDSSRT as a password.

Cobra car:
Enter TRTTLL as a password.

Cheetah car:
Enter NRNNRR as a password.

Panther car:
Enter YMSTTR as a password.

All cars and cups:
Enter GGWWOO as a password.

All cars and tracks:
Enter WLLVDD or WLLYDD as a password.

Enable all codes:
Press Left, Up, Right, Down, Z, R, Down, Left, Up, Right at the player selection screen.