I got my first one on super speedway
I heard that if you did it w/ the escudo w/o pitting in that you get the F1 car, It worked for me the first time. But I tried it on my friend's game and it didn't work, making that trick bull****. the Laguna Seca endurance is a good one too. It takes you awhile, but you have a 50% chance of winning a F1 car...two of the best F1's too. And even if you don't win an F1, you coudl win a Calsonic skyline, which would be nice for the red emblam championships, OR you could win the altezza lm racecar, which is useful for the altezza series (obviously)