You sound exactly like a guy I talked to in West Yellowstone last week, thought he knew everything about ski-doos, but had never heard of Big John and thought his mountain set-ups must suck because no one from the midwest knows anything about mountain set-ups.
The fact that it was set-up by a minnesota dealer though does make me think that the M8 still might have a little left on the table.
As for properly setting up all the XP's and Dragons and what not, they should be well set up from the factory, like the M8, which is why I think it is the sled of the year.
Oh, and according to the latest Snowtech, the M8 is 13 pounds heavier than the XP. And the Dragons aren't cranking out the promised 154hp, more like 146 range.
By the way, expect 10 more hp from the M8 from the the factory in 2010.
And I do ride a ski-doo, so my opinion is about as unbiased as they come.