You might want to wait until next year anyway. With Skidoo and Polaris both touting their new 850 engines, how long can it be before Cat launches a C-tech 850 of their own? Or knowing Cat, they will probably make a 869cc and call it an 850.
Off topic slightly, I apologize, but with all the technological improvements hitting the snow today, I am starting to think I would like to see them resurrect the 700 engine class. The 600s are in the 120 -125 hp class, the 800's in the 150's, the 850s in the 160's. I would have to guess with the new technologies available today a 700 would be in upper 130's to the low 140 hp range?
The biggest thing I would like to see go with that would be a considerable weight savings from going to a smaller engine. Right now the 600 and 800's sleds weight essentially the same. I know it's not economically feasible to downsize the size of the snowmobile to match it's engine size or horsepower, but if they made a 600cc sled 3/4 or 7/8 the size of an 800cc. I think it would be a real kick!