Ok just collected it and drove for only 5 mile, this car is a complete beast. Whereas I always felt on top of my 997S, I really feel intimidated by my GT3. The roar in Sports is unbelievable, the whole car is visceral in the extreme, more so than the Mk1 I had driven.
As I mentioned on another forum, my old 997S even with lowered suspension felt it "counter-sank" in turns compared to this, whereas the GT3 tilts on a level plane with a lower center of gravity. You can really feel the difference there. The gearbox is heavy duty, therefore a bit slower and short shift but better and more solid.
One problem is pedal placement on RHD, I cannot get to the foot rest without touching the clutch, very annoying.
Not enough time for brake feel, although felt extremely good, and certainly not a chance in the world to jam them for proper bedding in in Central London!
Sport bucket seats are excellent but have only 1 posture, a take or leave proposition so make sure they suite you, they are very good for me as long as I do not slouch.
I finished my other message by saying I felt in a cage rather than in control, I am in awe at the beast!