Perhaps 6 or 7 years ago there was a fella who had tracks or got them and operated at higher elevations. He ended up going to a turbo to get the ooomph to push the tracks at, what to him, was acceptable speed..............
Another fella, maybe last year or the year before, took his 900? from down in Texas I think up to the high country in Colo for hunting..........I seem to remember that he had no complaints; but perhaps there was talk about being some off.............
Maybe some of the older members on here can help me remember these things as these old brain cells are taxed just knowing what day it is..........
Perhaps a search, under "turbo" and or "tracks" and then plug in WAYYY WAYYY back...........We have a good search engine on here so maybe try:
Altitude
Turbo
tracks
????...................God bless.......Dennis