Thing is, 600hp is nothing nowadays for a GT-R. I bet most cars are running that easy with a stage 1/2 so perhaps Nissan are leaving the tuning to us punters and so not putting in the effort (development, cost etc) to do it themselves for a car with limited remaining shelf-life? Or put another way, if Nissan wanted to give the car more power why haven't they? Even 700hp would be easy for them to do EXCEPT perhaps for getting the car through stringent emissions test??