Originally Posted by swamp2
The main reason is that Nissan is a big liar.
Everyone agrees that the GT-R is pretty substantially under-rated. I have not kept track carefully since the initial launch of the car but in that year most folks in the know agree that the car is probably putting out much closer to 530 hp opposed to the spec. of 480. The cars advanced ATTESA-ETS (traction control), AWD system and launch control contribute as well.
Just doing a quick and dirty with the Motor Trend numbers, the new GT-R continues the under rating trend, showing around 580 HP on a 530 rating.
Thus, Nissan and BMW continue the skullduggery, along with the new mercedes "63" twin turbo cars. Works for me, actually, and reminds me of similar skullduggery with U.S. musclecars of the late '60s.