Evil_twin, I think you've hit the nail on the head. The 911 Turbo represents the ultimate Porsche (short of the track-ready and too-punishing GT2 / GT3s). This is the car that the CEO can drive to work every day, rain or shine, but still afford a lot of 'car guy' bragging rights as being one of the most ferrociously accelerating beasts on the road. The driving position isn't too extreme (compared to other super cars); there's room to take someone out to lunch and still put the briefcase in the trunk / backseat. And it's forgiving to drive around town by what I've heard / read.
Conversely, an F430 or Gallardo represents a less civilized manner of transportation. Not everyone wants THAT much attention (ie. parking it in the boss's spot at work every day). In days gone by, a Ferrari or Lambo needed much more constant tuning and attention -- I'm sure that's not the case now, but presumably they still require more than a Porsche? The Italian super cars are less comfortable and less practical, and while I know none of these cars are a picture of practicality, the Porsche really does make a good case for itself for being a daily driver.
Z06s and Vipers certainly offer the performance, but not the class or cachet befitting a high-level executive's daily car. (Don't get me wrong, I would ABSOLUTELY LOVE a new Vette -- even a base model).
Then along came the R8. Suddenly another car could be driven daily to the office because it has the class required; plus offers genuine super car looks and performance. This should be the car the Porsche guys lose sleep over.
The GTR's greatest downfall is still its brand. Cars costing upwards of $100,000 are ALWAYS a luxury, and the people buying them are looking to show off or brag to a certain degree. To some, it's badge bragging. To others (and likely those who buy a GTR) it's bragging about the extreme performance and storied history of the Skyline. The vast majority of the population at the Country Club or fine restaurant valet will look at someone showing up in an awkwardly-shaped Nissan and turn their noses up to it. Impress the chicks? Unlikely unless they're the type of woman who would hang out in a forum like this. Very few people appreciate cars and peformance thereof the way we do here.
The GTR is very much like the STi from a few years ago. Gawdy, but those who know it well, really appreciate the beastly performance that beats the crap out of anything priced anywhere near it. Ultimately though, the people who can afford to buy one will likely grow tired of it within a couple of years like they did STIs and then move on to the newest automotive trend to show off. We can only hope for Nissan's sake that the population of true, die-hard car enthusiasts who will actually use the car for weekend track events is big enough to support their tremendous efforts.
