All Tracks
Start a one-player game, then pause and goto options. Select 'sound' and highlight 'FX volume, then press L1+L2. the game will now be 400% complete.
Upside down
On the circut selection screen, press and hold L1+L2+down+X. If it's worked, an arrow will appear under the track name. The racing veiw will now be turned upside down.