This is a lot easier
A much simpler and less costworthy way to do what sniper spy is saying is just use a normal car and beat the first two special condition races. The first will get you a car w/ 760 hp not 720. Its the cadillac cien 02. The next race earns you a rally car which you can use to beat some of the other special condition races for more cars and then you can sell it once you get a better rally car for over 250,000 cr. I wasnt a member of this site when I did this and was 1.8% of the way through the game and had some cheesey nisan that had only a few xtras staked on.
We have more cheats and tips for this game here, Gran Turismo 4 cheats
Comments for this hint