Keep in mind all these engine rumours and sketches etc. are not coming from Honda itself. Just because we waffle on what might be in the next gen car doesn't mean Honda hasn't had it nailed for 2 or 3 years, awaiting certain conditions or criteria to proceed with detailed engineering and retooling of the factory.
Chevy Corvette Z06, Nissan 350Z twinturbo (when they introduce it in a year or so), Mustang SVT Cobra already do that, to name a few... this is nothing new. My bet is that if Honda releases a new NSX, they've got the Ferrari 360 and Porsche Carrera 4S in their gunsights.