The only real Nytro race chassis are hand built units built by Yamaha and provided to a very few of their sponsored factory racers. They are in a continual development stage and the sno-x versions were by far the most exotic and expensive. Problem is, with all the money and exotic materials, they really didn't work any better in sno-x than the other three OEM's, 2 stroke, stock chassis based race sleds. On the other hand, the XC versions have real potential. The bad thing is the crowds, exposure and press and TV coverage is not there for XC racing. Hopefully that will change in the next few seasons.
The consumer Nytro is a good chassis that can be made to work. It is by far the most competitive 4-stroke chassis available for XC or sno-x racing. But, it still leaves something to be desired compared to the 2-strokes. If you use a dirt bike analogy, we are kind of stuck in the mid 80's with a Honda XR 600 4-stroke chassis and weight compared to the 2-strokes. Things will change, but Yamaha has not yet provided us with a snowmachine version of the YZ 400F. They are getting close and the EPA's restrictions on 2-strokes will only work to our advantage. I firmly believe 4-strokes are the way of the future but sled racing is not a priority of Yamaha, especially in this economy.