Ruzo, I have the Continentals and they work OK, certainly not like yours. Lots of snow too. But just to make you feel better you should try the 350Z in snow. I've been told that they are worse and don't offer an all seasons from what I have seen. Just to give you a comparison, my Firebird and Camaros on summer tires where worse on ice & snow than the Xfire so with all seasons, I would imagine, would make them about the same. I only lost 2 days of driving so far this winter and that was during 2 feet of snow. I didn't even try. The Continentals work reasonable in the winter and give you a little better launch in the summer. What I mean is that you can dump the clutch at around 3,000 and get just enough wheel spin to completely avoid the bogging that some of the guys are experiencing with the Mich. You won't have to change tires for the seasons. However, if you add a lot of hp to the stock model or do a lot of road racing, then the Mich. will more than likely work better.
Of course this information would be more useful to someone who hasn't already got a set of Mich. already on thier car. Just more stuff to make you say......HUMMMMMM????