Get money for prize in race, buy new car and improve their
At the beginning of the game you have only one cheap car. Occupying prizes in the race, you get cash prizes. You can improve your car (separately improving engine, tires, body), in order to it was more powerful, had a good tires friction and was more resistant to shocks. Also, you can buy new race cars and improve them. Taking the prize will be open next level, which is more difficult, but also cash prizes are above.