Just FYI Porsche has a 10 year Limited Corrosion Warranty (mostly covers the body panels). If I'm not mistaken Porsche has been using Galvanized steel for the body sinc the late 70's or early 80's. That's why you don't see even the most run down looking 944 with body rust. The battery tray is a different story, though.
I drove daily, a 91 S2 for three years and the previos owner used it as daily also (in PA). The only rust i had was the heat shield on the exhaust.
I drive the Box daily and don't fear the snow or salt down here in NoVa. But if I lived in Buffalo again (I lived on Grand Island) like BuffaloBoxster i would put it away for the winter. That place just gets too much snow. I think Buffalo coined the phrase "Winter Beater"