Not sure if it's been mentioned but make sure you download the extra map from the extras menu.
There are 2 - one under "Exclusive Content" (and it's STREETS wooo, exclusive )
The other is under Comcast Map or something. Enter "Comcast Faster" in the redeem code to unlock. It's already on the disk, so I don't really see the point but hey.
Oh I know - without the Comcast sponsership it would no doubt have been a paid dlc. So fair enough I guess.