Ok well I has some good inputs from SEV and others and I want to thank them both for some guidance. Still there is confusion and doubt here and looking for more help.

Well it will 100% surely be the CAB for my next purchase. It is big bucks as you all know so I am hoping for some debate and arguments for and against. Coupe is great but I already own a car with a roof. I wont be tracking so you would think the argument was settled. Someone did bring up a good point about performance being down (2/10 of a second). Well I would not call that drastic..a cab S can still give an M3 a good spanking. However on a serious note I need some input (since I have not driven them extensively) on how much less rigidity does the cab have on the coupe? And some thoughts on C4S and C2S (realizing the CS is much more nimble).

Thanks All.

 

I don't know whether Porsche ever published the metrics re the rigidity of the 997 coupe versus cab design. Perhaps you can Google it. I will say that I'm generally impressed with the design of the cab chassis. It isn't 'perfect' (i.e. the coupe is 'perfect' in that it doesn't indicate flex in the areas that a cab does), but it eliminates many of the classic convertible structural weakness symptoms: windshield frame flex is near zero (the most visibly weakness in most convertibles), front cowl shake is nil as well. Nothing in the wheel/steering shaft or window seals (when top it up). There is enough flex to hear slight movement in the door jams (another classic sign) which is annoying and the single greatest indicator of it being different from a coupe.
In theory, having tightened the suspension considerably with Damptronics and H&R bars, the flex issue should be more noticeable, but I haven't seen it.
So, in comparison with the coupe, it is not as good, but it's very good, and really quite excellent for a convertible. I have a sense that Porsche is approaching the limit for a alloy chassis. I suspect that the cf chassis in the Carrera GT or Mercedes McLaren speedster are radically better. But they ought to be.
Finally, how much this additional flexing impacts handling accuracy is beyond my level of knowledge or driving skills.

 

Good point Verde, I always thought this was the key question!

I'd bet that less than one percent of the readers here would improve there times, going to the country club, in a coupe!

 

Porsche has done a good job with the cabs as far a rigidity is concerned. They still are not as rigid as the coupes, however, and are heavier. Therefore, handling suffers a bit.

 

I believe a few here have actually even gone so far as to state their preference for the additional flex in the cab model. If you're worried about it, I would go rent one for the day and drive it around, The rental fee is a small price to pay to avoid the potential mistake you may be making.

 

That's interesting. I have not read that. I wonder what the motivation is for seeking additional flex in the chassis? To be clear, the (very limited) incremental flex in the cab does not translate to ride quality/smoothness differences. The additional flex evidences itself in a few shakes (in the areas I previously mentioned), small variances in steering geometry that occur when this flexing occur (it would require more skills than I have to notice this difference) and a rattle or two (e.g. from the door jams) that come from this flexing.
It IS true that some companies that make a matching spyder and coupe put softer suspensions in the former, to minimize pounding on a fundamentally weaker structure and plays on the assumption that convertible owners don't want to drive their cars as hard. To the best of my knowledge, Porsche uses the same suspension components in both cars.
The idea of renting is a good one. But I'd add that unless you are an experienced 911 driver, it's unlikely that you'll notice the difference in structural rigidity.