There are a handful of track variants in the game that seem to only be accessible via cheats, so I thought I'd archive the ones that would be useful for getting everything you'd need to get started with this game.

Input these cheats while in a race.

UNLOCK ALL TRACKS Z, D-Pad Right, Z, A, D-Pad Left, D-Pad Left, Z, D-Pad Right, A, C-Down, Start

UNLOCK ALL GT1 CARS Z, D-Pad Right, Z, Z, Z, A, C-Down, A, D-Pad Right, Start

UNLOCK ALL GT2 CARS Z, D-Pad Right, Z, Z, Z, B, C-Down, A, D-Pad Right, Start