I am sorry, but I don't like this game. When that is said, the visuals is really good. The level design is pretty good. The car controls is good, and it felt like driving a real car. The audio is pretty bad, but it's not that bad that it made me stop playing the game. None of those things is not what make me say that I don't like this game.
But for me it's not fun driving time trials or against a AI I am not near able to beat. Instead give me one map and use the time on making a split screen racing game. I believe you could have done this, and I am sure it would have been a much more fun game. But of cause the choice is yours, and overall the game you have made is pretty well made.