If you are participating in a race, you would opt for the first rather than any position since that is where the big bucks. Also, people will not notice you if you just got the third or second position as the first one to get to the finish line is the only racer that is the best for them.
In this game, you can't proceed to the next track if you can't get a number 1 position. You can still get a part of the prize money. You can use it to upgrade your car, but you need to remember that the large sum of the money goes to the number 1 spot.