John,
I know you really want one of these cars to work for you. I've got one piece of advise for you...
Give it up.
There are multiple reasons they are a horrible choice for the northeast or midwest in the winter. Its easy to forget (in July) that in the winter its cold- like below zero cold, and that it snows- several feet sometimes, and that they put salt (lots of it) on the roads. Assuming you could stop all the air from infiltrating the cabin (you can't), and you could get enough heat (without a gas heater, you're short on luck), you'd still have a car with a fabbed up suspension/frame set-up which would be just waiting to rust away to nothing. Guys' chrome gets rusty from washing their cars- driving it in salt? Its really a BAD idea.
No matter what anybody says- unless you pony up for an IM, or subi-tub, this is a nice day, planets-are-all-lined-up kind of car. Even with the IM and subi-tub, I wouldn't want to drive it in the depths of winter. Why in the world would I risk my pride a joy being trashed for the sake of a couple of months (OK, more than a couple) of "stylin'"?
These cars are NOT modern. They are not a stylish Miata, or a retro-looking Z3. They are full-on retro, for all that means. As soon as we can all deal with it, the happier we'll all be.