Wow, I'm really impressed. Almost perfect for my taste.
If I had to change anything I would like a little more oversteer, and same for brake balance, as in that braking and steering makes the car slide a little. This is not really a problem since the handbrake can force the car into a slide anyway, but I prefer the normal steering/braking to do that a bit more already, too.
That's just nitpicking about my taste though. All in all, I would love to see a finished game with these graphics and these driving physics/feel. So please keep up the good work!