This has the ability to be huge. Exchange points for gas discounts or off maintenance? Lots of other potentially game changing things could be added to the game mechanics of an automobile platform.
Separate player tags would be awesome and could be accomplished with fobs or sign-ins. Or perhaps you just register your high scores?
For more in-depth configuration you could include wifi access and a browser portal to set up drivers or post to your facebook wall. OK, ok it could go downhill quickly. :)
Imagine getting into your car and having it decked out as a fully operational 80's arcade console. Wood paneling, quarter slots and a big red 'Start' button.
I wonder if this even has to be a car company. Why not a mobile app company that uses a Bluetooth module on the ODBII port to get info on the vehicle, MPG, and driving style. Then uses that data to reward points.