umm... I don't know, I love outdoor raves, I don't want to turn you off, but you won't miss much if you skip the FMP and instead find a something unique to do.
I didn't like being around that many idiots, there must be 10 000 people and at least 1000 of them are young idiots getting way to messed up, everyones peeing everywhere, everyones tring to rip you off.
Lots of people like it and some even say its the best thing they ever seen, I might be a little jadded after attending British Columbia's best outdoor rave type events where everyone is super cool, peaceful, no cop problems, good and famous djs, .... the don't compare the FMP seem like a bunch of kindergardeners who peed their diapers compared the the real scenes everywere else in the world.
I would consider trying to get tickets to some sort of cool club in BKK or Chiang mai, or some swanky dress up jazz thing or something whee you will spend NY with the classy thais and westerners alike..
Just a thought, but you might have a different experince, I was alone and sober and 29 and basicly left after 2 hours or boredom, perhaps if I was with friends it would have been better.