gurdas,
I'm not sure if you are sitting around still waiting for an answer, but the way you do it is.
If it's a 5 race series (which I think it is) and you saved after the 4th race, just let it pick your car and if it isn't the right one, keep hitting the Triangle button until you get back to the title screen (where you choose Arcade or Simulation. If you scroll down the list, you'll find Load Game.
Just load your game and it'll take you back to your saved point at the end of race #4.
Now, just to save you more time. When you start Race 5, just drive for a couple of seconds, then choose to exit the race. You should be far enough ahead in points that even if you take a DNF, you'll still win.
If you get the car you want, good. Go save the game. if you didn't, repeat the same process.
I personally would choose the Type R NSX, but you may like the S2000's. Either the Spoon or the Mugen. I'm not sure about the price on the S2000's, but the NSX should get you about $25k (if I remember correctly)
I believe you get 1/4 of the "purchase price" of the car. And, since the NSX is worth about a $100k (again, just going my memory), then you'll get 1/4 of that.
Anyone, feel free to correct me about the values.
