The #1 cold weather option is a hard top. This really is a must have for winter driven cars. It extends the life of that very expensive cloth top. Labor to replace a top is not cheap either.
As for me my 2000 s came with a windstop and the mesh wind stop thing that goes in the roll hoops. THat would have cost me $350 if the orginal owner didn't spring for them. Also, he went for the full audio upgrade and boy am I glad he did.
I driven many convertibles and this is by far the best "out of the box" top down audio experience I have ever had. 80 mph and no distortion, crystal clear.
I do however wish the owner had added the aero kit package. Sideskirts are a must have IMO.
and I would suggest looking into a used Boxster. Aside from having better styling
Its an awesome bargain. I can honestly say there is not one thing on my S I don't like a great deal. Get the 987 in a couple of years when they have refined it.