To unlock the Super Race Modes, Complete each race type once, including GP Mode, doing Bronze Silver and Gold cups. After this, you will see the credits. When you resume playing, the Super Bronze, Super Silver and Super Gold Cup races for each race type will be unlocked.
Unlock Dragon Parts
Complete the Angel Cup. From the main title screen, go to Options then Change Name. Enter ''DRAGON'' as your name to unlock the Dragon parts. You'll get a screen telling you they are unlocked. You can change your name back anytime after that.