Nice write up. I*ve had my GT-R for the same amount of time but half the miles. I agree with everything you said, but some things bother me more than you.
The transmission is towards the top of my complaints. I think you described the *issues* quite well. Temperature is a huge factor in mine. Shift flair on the 1-2 when cold is terrible. 100% gone once at operating temp. It also acts confused when slowing down to around 10-15 mph for a turn. Get back on it and it hesitates, bit of a flair, then settles. If I manually select 2nd in the same scenario, it*s not an issue(unless it*s not at operating temp). I suppose it could be a result of the AAS someone posted. Although it seems like that will hold gears longer, which shouldn*t result in flairs.
Second to that is the seats, which you also noted. I don*t have much meat on my bones. My thighs are almost throbbing after an hour.
I am surprised you didn*t note the power loss issue that occurs below freezing. Did you ever get any answers on that?