As I tried to explain below to another poster, it's because I would rather have 1 car than two at this point, and the Cayman seems like a better bet than the Box, if that's the case. But if my love for the Roadster prevails over my desire to have just 1 car, then I'll go for the Boxster and keep my GTI as a 'practical' car. Keeping and (paying for) 2 cars is $$, so the TTR will go and I can manage a non-S, and my GTI. Is that clearer? 
Clear. Your previous post explained it.
Money and the practicality (almost one and the same) issues hold me back from the S. To put it another way, the only 'S' I can afford is the Cayman, to my way of thinking, as odd as it sounds. Initially more expensive, but I would be unloading 2 vehicles instead of 1, not to mention insuring, storing, maintaining and generally squandering my time obsessively, over 1 instead of 2 cars! Better in the long run, I think. Now if you guys convince me the Boxster S is every bit as practical and good a long-term prospect as the Cayman S, then it's a win-win! BTW, I've never been this undecided about a car before; I never hard to shop or compare, because there was only 1 vehicle I really wanted. But these 4 Cayman and Boxster models are giving me fits!
For me, the roadster part of the Boxster was THE largest attraction. The way the engine sounds with the top down is just magical -- a four wheel motorcycle with all the safety that comes with it. And I don't think I'd be salivating as much over my impending early Saturday morning drive if it wasn't in a roadster. So if it was me, and if you don't plan to track much, I'd just keep it simple and forget the Cayman.
Consider unloading the two cars and get a Boxster S with just windstop and heated seats (Bose or not) + a used Maxima/Camry/Accord/Civic/etc for $6-9k to drive in winter or around town (especially if you live around NYC). That would simplify care, insurance, and maintanance a lot, and allocate cars optimally between pleasure and utility. Again, just IMHO.