Um, actually, you only need to join a series of 4 races. Because if you get first, you're +4pts on the #2 dude, and do that two more times, and you're +12pts. Now seeing that you can only get 10pts for 1st, you've basically insured that they can't pass you on the point scale.
Here's the point scale:
1st- +10pts
2nd- +6pts
3rd- +4pts
4th- +3pts
5th- +2pts
6th- +1pts
Now if you quit the race, you get +0pts, so you need to have at least 11 more points than the 2nd place person(that would make you first, yes) to make you win.
Although, I never knew this was a cheat. If this is a cheat, wouldn't quitting after a race starts to just skip it, but you have to save and try multiple times so the 2nd person, the person behind you pts wise, doesn't get 1st in the race and pass you up points-wise be a cheat? I've never thought of that as cheating. I guess just skipping races is cheating too. I originally didn't want to skip, but after I have a 30 point lead, it gets really boring racing using a Camero Race Car, going against regular Vipers and Corvettes... It even gets boreing racing those with the Mustang....