Sounds more like the sales-fellow was a dope not necessarily a lair. Until he found out he was wrong and started trying to cover his butt. Unless you really drive the car hard you'll likely never notice a 10 hp difference. As is it's a great car. I'd just try to see what I could get out of the dealer as his way of compensating you for the misrepresentation and for keeping you from complaining to the regional bmw offices, better business etc. As you are in Canada, you should probably have a set of winter tires. I'd shoot for a set of winter wheel/tires - that would be a great deal for you. (of course the above is my opinion, which was unsolicited, but for some reason I always think people want to know my opinion)
Good Luck with however it turns out.
jfh
Good Luck with however it turns out.
jfh