I have had two brand new Boxster GTS4.0 cars, the first one I specified myself, the second was a showroom car so no choice;
The things I miss most that the second car doesn't have are:
Speed limit indicator (camera based) - surprisingly useful, as the GPS data is often wrong / out of date.
PDLS+ LED lights. The PDLS Bi-Xenons are nothing like as good
Lane Change Assist. Didn't think I needed it but my wife said it better to have it. Turned out to be useful on motorways and on track. Obviously can live without it, but I'd spec it again if I get the chance.
PCCB brakes. Really miss these, mostly for the improvement in ride quality, but also smoothness and power when braking. Academic at the moment as not currently available
Things I'm not sure about.
Multi function steering wheel with heating. I prefer the steering wheel unadorned, and it's much nicer to use the column stick for the computer / right hand instrument screen archer than the rolling button on the wheel. However I do miss the wheel being heated, as my car is a Boxster. Not as much as I thought because the second car has faceted wheel which is good when wearing gloves. What I'd really like is a heated wheel with no buttons.
PDK gearbox. first car manual, second PDK. Still not decided but lets not go there now.
Things that are better in second car.
18 way seats. Surprised by this but against expectations the 18 ways are more comfortable than the manual ways. better distribution of padding and lumbar support. I was very happy with the standard manual sports plus seats but these 18 ways are better still.