Hi Hacksaw,
The Canadian Coleman site does not mention using automobile unleaded gas in their multi-fuel stoves at all, but the USA site specifically mentions not using Canadian Automotive Gasoline in any Coleman product (including multi-fuel items), follow the link in the original post for the exact warning.
I checked out the link you provided about gasoline additives, there is sure a lot more stuff in gas now than there used to be.
Thanks,
Mike