I just played the demo on Xbox360 and WOW! It's so much different from the previous games.
To answer some questions on here: it is during the day and I did hear it will be at night for some races. I don't know though.
There are no police chases as ProStreet as it is an organized series and closed tracks.
It is still more of an arcade style racing, but it is also more realistic as well. This makes for tough driving all around. Think of it as a blend between Juiced2 and PGR4.
The graphics are as real as it gets! Everything about it is related to the real life and I love it. I am definitely buying the game when it comes out.