And a porsche is just a porsche. A mass produced car like Nissan, holden toyota etc. Dont let the euro price tag fool you.
As for build quality, I'll take the nissan, No porsche will stand up to 740 thousand kilometers of abuse that i handed out to my one before, And probably not the 413 thou that its predecessor dished up. both of these vehicles (3 litre and 2.8 litre) did it without major surgery. just regular servicing and brake and exhaust updates as required.
As for facts. It would appear that you have some nissan inside running, How else would you know that they used a dodgy driver in the porsche or that it will be detuned for production.
Now that the "gentlemans agreement" is out the window its gloves off and no holes barred. I dont think Nissan will be the only maker in japan building cars that border on the super car title.
Your comparison between the vw and the bentley doesnt wash. One is not a mass produced car and it isnt thevw. To use this yardstick we should perhaps be comparing the gtr to something far more super carish than a porsche.
You sell the japs short. They build some good shit and the gtr is right up there imo. It can fight way above its weight and with selective mods can tackle some of the true heavyweights.