ohhhh...my goodness...you asked a LOADED question.
Tires, Motors and Chassis will all depend on your track and it's conditions. In general, next time you're out there, ask one of the fast guys what's working for them, because odds are, they've got the hot ticket already.
Basically, the harder packed the dirt on the track, like clay, the smaller pin you will run on the tire. So, Clay tracks will generally use a "taper Pin" tire. Wheras loamy, deep, rutty tracks may use a larger pin like the "Kingpin" or "Ifmar Pin" The deeper the top-layer of dirt gets, the larger pin you'll need on the tire to compensate.
For the P2K2, the hot gearing has been 18/86. I personally liked the feel of an 18/88, but I run on a small, tight track, so I need the extra punch out of the corners. The smaller the track, the higher the ratio, the larger the track, the lower the ratio. The hot motor in my opinion is the MHP (monster horse power) stock motor. They're just a really all around great motor. again, ask the fast guys in your class what they're running.
This is where it comes down to user preferance. I like the standard matt francis 1 fury body. I think it's a beautiful body, ultra low profile, aerodynamic and just cool looking! The new MF2 body doens't to anything for me, but some swear by the handeling characteristics it presents. I've ran them all, I couldn't tell ya!
again, the fast guys know their stuff...but, a good starting point is always the stock (default) setup losi provided for the MF1, you can find it here: http://www.teamlosi.com/pictures/jpe...xtnatsmatt.jpg
I personally like the Brian Kinwals setup....which many people have come to use is:
32.5 wt oil
.125 (or just find the largest internal limiter you can find...use that one)internal limiters
2"blue spring located inside on tower and arm
camber link 3b with 2 washers
camber at -1
toe at -1
32.5 wt oil
2.75" yellow spring located outside on tower and arm
camber link 2a
hub carrier spaced into the middle on the arm
1 spacer under front of arm carrier for anti squat
camber at 0
That should do it for now! I hope it helped a little...let us know if you have any more questions! Also, don't forget to make a trip out to your track and ask questions!!! the fast guys know their stuff!