welcome to the club. That sled is mint, wish mine had half the miles it does but even with 5300 it's just broken in. Is this your first yamaha? you may want to go join over on totallyamaha for the wealth of knowledge to be had. I was very experienced with yamaha outboards and bought my MM as a result of my experience with their quality.
Here is my build thread from over the summer, but it covers about 2 years worth of work with lots of details and pictures.
151" Mountain Max Build
If your going for a bowl climber you can get into chaincase drop and roll and custom tunnels but most of that stuff has dried up, you can find it used that's about it. For a boondocker tree sled a 151" with a 2" challenger is about tops for setup. My sled will ride wrong foot forward all day long with the new bars and now with the longer wheelbase and higher front end from the viper arms it will lay on its side with no effort at all on flat ground. I'm looking forward to see how much easier it is to ride in the trees this winter.
Don't buy into the hype that trailing arm sleds can't do what a modern A-arm sled will. This is a great platform to learn the modern riding style. I compared the measurements from the snowest 2013 800 sled review with my sled and critical measurements like ski bolt to foot placement, board width and length and overall sled width width were within a few inches of a pro-rmk and a pro climb. The MM has a narrower body shell and 4 in narrower track width than an rmk does, and once you pull the sway bar it will love to get on its side. Crazy Mountain Extreme was building RMK Edge based trailing arm sleds until 2010 if that tells you anything.
