I love the detail of the cars. being a car enthusiast, I can recognize the cars right away. other than that, not seeing much of a point other than for practice. I hate to blam it because it is just you practicing, but I don't think it needs to go in the portal. I suggest making this into a 'pimp my ride' game or maybe a full movie.
Might I suggest that you add some visible physics to this? Like, when a car decelerates, have the nose end of the car dip down slightly, and when it accelerates, show the car slinging back.
Verdict: Great art, but no substance.