Hi and welcome
![hello2 :hello2:](./images/smilies/hello.gif)
I'll try and give you my opinion, but like you have said, it's all subjective and as per the answer to question 1, all about personal choice.
1) yes is a personal choice. The older ones have become harder to keep water tight, but a new one will be ok.
2) by the sound of it I'm maybe a wee bit bigger than you, and I love my sports seats. I drove from Reims to Lanark last year, only stopping for fuel and the Chunnel, and walked away without any back pain. The new 991 has great feature that retracts the steering column and seat to help you get in and out.
3) get the best you can afford.
4) get the most you can afford, but since you asked, PSE is the main one I'd pick. Then sports seats, the rest will have very little effect come resale time.
5) again, colour is important at resale time. The sales guys will influence someone when buying a new car and the colours you've mentioned are easy to resell. I personally like cobalt blue and guards red. I think my next car will be a cobalt 997 turbo with a PDK box. I don't think they're obsessed, just aware that they're not buying the car to keep forever, they will sell it. Only someone who can afford to throw the car away will buy one they know will be hard to sell, and possibley loose money on the resale.
I like the PDK, but that's why Porsche make versions of all their cars and gear boxes. It would be pretty boring if we all had the same car, in the same colour, with the same gearbox and the same body style. You should buy what you want, can afford and will enjoy.
![Very Happy :D](./images/smilies/icon_biggrin.gif)