It's more of a face lift change and less a complete redesign. Nissan's way is to renumber cars as they evolve and develop rather than have a "mk ii" type approach. The obvious best example is the 370Z which replaced the 350Z. Okay a lot of changes and a might smaller but fundamentally an evolution of the car not a new car. The same will be true of the new GTR rather than a completely new vehicle. "evolution not revolution"