Risk averse...but looking at a BMW 850!
RWD or AWD...the reality is that most modern sports cars are doable in winter as long as you have decent winter tires. But the question is, just because it's doable, does it make it worth it? I drove mine in winter, and I wouldn't say it was particularly enjoyable....especially since you're always half expecting someone to slide into you at an intersection.
These cars can handle a lot, but personally, I still think the winning formula is Porsche + regular car/winter beater. Apart from the downsides of off-season driving, when you make it your 2nd (or 3rd etc.) car you also don't have to compromise so much on it's Porsche-ness and force it into your routine. Ie, you want a manual...but get a PDK to appease your significant other, or to make rush hour traffic easier. You want RWD, but get AWD for better year round driving. You want a convertible, but don't think it's practical. You want a funky color, but don't want to peacock at work. In the end, you compromise a lot of your dream for daily practicality...which kind of takes the air out of the fun balloon.
Never mind that there's something to be said for keeping the driving experience a little special, which daily-ing a car can erode. Going back and forth from the little sports car to the luxe-barge makes me appreciate both more.