You're comparing estimated flywheel horsepower in the first link, and AWHP measured in the second link. Of course there's going to be a big difference when you compare the two, this difference is due to drivetrain lossses. So basically you're comparing two different things!I dont like the gtr because it is inconsistent 2009 Nissan GT-R Horsepower: The Truth - Nissan GT-R Dyno Run - Motor Trend shows the car having 507HP and 2009 Nissan GT-R: True Power From the Dyno shows it having 450. I have also heard of some as low as 420hp. I would expect with how controlled the environment is that these cars are made in they would be within 10hp of Nissan 480 claim.
I respect what the GT-R can do and how much fun it likely is. But I think it looks like a factory ricer. An ugly car (that flies). From what I've read, I would not enjoy it as a daily driver. I'm sure it is a great track/race car but I appreciate that my M6 is a GT (and all that goes with that) and the GT-R clearly is not (nothing wrong with being another type of car, but just not for me).
BTW - I often see one in the parking lot where I work.