I optioned for the Natural Gray Leather in the GT3, now the car is two years old with over 10K miles and I'm very happy to see (actually not see) hardly any sign of wear on the seats and seat bolsters. The smell of the more expensive leather Porsche offers is amongest the best of all makes IMO.
I also had a '02 Z06 and like that interior better than the C6 Z06's, especially the center of the C6's dash. If I were to get the car, the first thing I'd do is to replace that vast piece of silver crap with something else... something carbon fiber hopefully. Whoever makes a good carbon fiber kit for the C6 will make a killing. Is there anyone out there?

 

It is a good looking car going down the track at speed. NEEDS after market exhaust! It

 

I dont have any wear on my GT3 either with full leather. The interior is no nonsense functional which is what you need in a track car. Its much better for its purpose than the luxury of the 997.
that M3 interior IS very pretty, much like a bently or Rolls. does it come with an umbrella?