http://www.caranddriver.com/carnews/11851/spied-2009-nissan-skyline-gt-r.html
"Nissan considered a V-8 for the next GT-R but has opted instead for a twin-turbo V-6, due to its lower weight and explosive power potential. A limited-edition 2005-model GT-R Z-tune, fitted with the now-superseded twin-turbo straight-six, generated over 500 horsepower, showing the potential of this car. Britain’s Cosworth is helping Nissan extract more than 450 horsepower from the upcoming 3.7- or 3.8-liter V-6 while still meeting emissions laws."
Looks like turbo V6, it is. No word on pricing in this article, but they have about a year to get it figured out. Hopefully, it won't be as high as originally reported. Then again, I couldn't afford it even if they dropped the price by half.