GOOZ

As your name. This will unlock every track.

Unlock Regular Le Mans Cars
Enter the Championship Mode and enter you name as:

MONSTA

This will make all of the regualr Le Mans Cars available for your choosing.

Unlock Every Championship
Enter the Championship Mode and enter your name as:

CARNAGE

You will unlock all championships.

Quick Race Reward
Get Gold (first place) on all tracks in the Quick Race mode and you will unlock a Jaguar XR9 LM Concept Car.