If you think about it they both have same power but the porche has more torque and is lighter. Also the Porche has ceramic brakes. And from what i see on the video the GTR both is flatter across corners and easier to handle, brakes if not better the same as the Porche and to top it off is quicker and since power to weight ratio is in favour of the Porche that Skyline must handle awesomely to make a better lap time. And still manages to keep the driver more relaxed.
"Lo there do I see my father.
Lo there do I see my mother.
Lo there do I see my brothers and my sisters.
Lo there do I see the line of my people back to the beginning.
Lo they do call to me
they bid me take my place among them in the Halls of Valhalla,
where the brave may live forever"