Posted below by GGS Subst3pz
I boosted it yesterday. we did it with 2 players.
The league expired at 12:30PM and me and my friend tried to get together in a lobby. Just search until you find each other. Then just stay in the lobby. Even after the league has expired, the lobby is still active as long as you are not leaving. After around 30min after the league expired, we were only 3 players left. Me, my friend and a random. We kicked the random out and did our wins with no effort. It's easy because after the league expired, no one could get in but out and as long as you are in the lobby, you could still do some races. Hope this helps.
Right now (at launch) the League event that is open is D class. I had some trouble finding a good car for this, then found one that blew everyone away. Won a 3 lap race by 13+ seconds.
Datsun 510, starts as a low E class car. I have shared my setup, search for my gamertag while in the car to find it. Its called "Won D Class Rain". Because the PI starts out so low, I was able to do full weight reduction and race tires, best brakes, etc... Most people just add power to low class cars.
My biggest advantage was getting a race in the rain. This car is amazing for rain. Hitting puddles does very little to it, and taking just about any turn while in 2nd gear is no problem in the wet. Its very well balanced. As long as you play it safe, remember to brake on yellow and not red, and do in/out/in maneuvers (stay on the outside before a turn, aim in to the apex, and follow out on the outside), you should be very hard to beat.
If you don't get rain, you may still win depending on the track. Its not a very fast car on straights though. If you join a lobby and its setup for a race on a track with lots of straights, back out and try again.
Video of the replay, and showing the information for getting the tune.