Unlock Challenge Mode:
In Endless mode survive longer than 3000 meters

Unlock Time Attack Mode:
In Attack mode Score 300 or more

Unlockable Cars
Complete your first ten races in multi-player then when you complete more races the following cars become unlockable

Pooka Race:
Race more than ten multi-player races

Galaga '88:
Race more than ten multi-player races

Red Shirt Rage:
Race more than ten multi-player races

Shy Guy:
Race more than ten multi-player races

Mario Racing:
Race more than ten multi-player races

Caddy Car Race:
Race more than ten multi-player races

00-Agent Car:
Race ten multi-player races using a single cartridge

DS Car:
Beat Ridge Racer Extreme in Extra Mode

Bounus Cars:
Win all the Platinum Grand Prix races to unlock all Bonus cars in the game.

To be able to unlock a car in Car Attack mode and be able to get that car as an opponent in Car Attack mode win the indicated Grand Prix. After defeating that car in Car Attack mode you will then be able to drive it in Car Attack mode.

TR Xevious Red:
Grand Prix 1

RT Pink Mappy:
Grand Prix 1

RT Blue Mappy:
Grand Prix 1

RT Bosconian:
Grand Prix 2

RT Nebulasray:
Grand Prix 2

Galaga RT Red:
Grand Prix 2

RT Xevious Green:
Green Prix 3

Big Racing Team:
Grand Prix 3

Galaga RT Blue:
Grand Prix 3

13th Racing Kid:
Grand Prix 4

Galaxian Paradise:
Grand Prix 4

Micro Mouse Mappy:
Grand Prix 4

Age Solo S:
Grand Prix 5

Assoluto Infinito:
Grand Prix 5

Racing Team Peach:
Grand Prix 5

Atomic Purple:
Grand Prix 6

DK Team Racing:
Grand Prix 6

Terrazi Terrific:
Grand Prix 6

Burning Nightmare:
Grand Prix 7

Racing Team Luigi:
Grand Prix 8