autoguide article may explain lack of Z updates.

BrianMSmith

I do not think the Z makes Nissan any money, it's not a "halo" car, and therefore will not likely survive a product line replan. It is simply too great a car, too high of quality, and selling at too low a price and too few units. It costs Porsche no more to build a 911 Carerra S than it does the Z, and look what those sell for at comparable volume. Ford can build an F150 truck for 1/4 the price, sell millions of them worldwide, and charge about the same price with bling.