With the convertible top being a Plastic of some sort, and the extreme cold and the weight of the snow, I would store it indoors over the winter to avoid unnecessary stress on the top.
I suppose this could warrant you buying a hard top for outdoor winter storage

or some kind of structure to protect your $65,000+ car.
A car lift sounds like a good idea too
Ask your wife where her other friends park their $65k cars over the winter?
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"It broke because it wants to be Upgraded

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2012 Porsche Performance Driving School - SanDiego region
2001 Boxster S, Top Speed muffler, (Fred's) Mini Morimotto Projectors, Tarret UDP,
Short Shifter, Touch Screen Dual Din Radio, 03 4 Bow glass Top (DD & Auto-X since May 17,2012)