Go to the Extras menu, then select Cheat codes.
     Input the following passwords here:

Password:      Effect:
942785         Unlock all Challenges
761492         Unlock all Championships
611334         Easy Steering
505303         Takes no Damage
467348         MM View
374288         Miniature Cars
171923         Free Drive
112337         Unlock all Rewards


Track designer unlockable parts
     You  can purchase extra parts to use in the track designer in the
rewards shop.

Street style: Beat tier 13
Track pieces 9-32: Purchase 'street style'

Unlock Pro Tour mode
     Pro  Tour  mode  is  a  harder mode where you can only use manual
gears and the AI are of a harder difficulty.

Pro Tour mode: 100% completion in World Tour mode