That one does look intriguing.
P11: since you know a guy who knows a guy who knows a guy who knows a guy who once touched a treadway ponytail, get one of those guys to go with you to look at whatever you buy. You're in canada and I know the only sleds up there are skidoos.... it should be pretty simple to find someone who knows those models. And for the love of god it sounds like you should not ask your neighbors ANYTHING :D
Like AK said, bring a compression tester. That should give you an idea if anything is up with the pistons/top end without tearing it apart.