If you like convertibles, go for cab. Unfortunately I'm not a cab/vert person :P

 

Most cabriolets (any vehicle brand I've driven) exhibit some "cowl shake" that a
conventional hardtop version doesn't have.

Can't speak for the 991, but owned a 996 cab and it shook.

On the NSX-T if you take out the roof panel it becomes a different car....not in a good way IMO.

 

I have a 991 Cab and have owned most of the Porsche cabs since the 80's. I also, until last month, had a Turbo coupe that was a garage queen. I can tell you that the 991 is on an entirely different level in terms of a cab. It is amazingly quiet and the chassis is very, very stiff. I'm sure in the hands of a pro driver they can get a bit more speed out of the coupe. I've raced for years and in most drivers events I can lap coupes all day long in my cab. IMO you have go to get above 98% of the cars capability to extract the benefits of the coupe performance wise.

For a street car I'd go cab all day long...

 

I have had a cab and I currently have a coupe and it is a tough choice. I love cabs. I have a Mustang drop top. If I did not have that I would most likely have a P cab. That said, if you want to go to the track, you will be limited with a cab - some will not let you run. And, and this is JMO, there is nothing like the smooth line, without transition of the back end of the coupe. The lines of the new cab are much better than in the 997 cab I had in terms of matching the line of the coupe, but the transition in materials still breaks the smooth look, at least to me.

It is difficult to go wrong with either. Sitting inside, I like the cab. Looking at my car from the outside, I like my coupe.

Good luck with this choice.