If you want a career as a racer then you need to be the best or at least one of them. Otherwise, you should forget about it since there is no money for someone, who always lose in the race. It means that you need to make that you won't get the last spot since no one would be sponsoring you for sure. That is the reason, why you see those on the business always buying things for their car because they want to make sure that they come up on top. Also, practice makes it perfect and you would need to practice a lot, so that you can give your best during the race.
In this game, speed is not everything since you would also need to be able to control your car or you won't get far in the game. You can only be paid with money if you are able to get a good position during the race. That means that you need to get a position that is not the last. The prize money depends upon the position that you get and you could expect that the first car to cross the line would get most of the prize money.