I also live in michigan, and have stored my crossfire since the start of november. Its stored in my pole barn with a cover over it. Its not heated, and the car has been just fine like that for the last two winters. My 07 has never seen snow or salt roads. With it being in pole barn i'm able to go out and start it once a month and let it run, and if needed put a batter tender on it. I"m not so worried about it being heated, just so theres no weather on the car. :-)