I live in Canada, so unfortunatly I have been driving in the snow/ice forever. Listen to Mu$tang, he's got it right.One thought though, use about 4 bags of softener salt {50lbs each} or bags of salt for doing icy sidewalks,in the trunk If you use bags of sand when it gets really cold the moisture in the sand will turn it really hard.If you hit something or someone runs into you, what you have in the trunk will keep going right through the back seat and try to hurt ya.Also the salt/sand mix they use on the streets is really nasty to the body of your car,[rust] so we sports car guys here all have winter beaters.
Good Luck!!