GRID Cheats

To unlock Bonus cars, from the main GRID menu go to options:

To unlock Ninja Difficulty, get every trophy and complete every head-to-head race in Grid World.

Achieve a first place finish in all of the global events, which will bring you to one last head-to-head race. After winning that race, all of the cheats will be unlocked in the same place where the cheats are otherwise inserted in the game.

Acquire each of the other regional licenses in the game then, earn a million Global Points to unlock the Global License.