I'm new to the 350Z and just recently purchased a 2005 350Z Roadster. I've had many cars over the years including a few Acura NSX's. Acura had a similiar problem with the NSX upon introduction. Owner's were finding that the tires weren't lasting more than 7-8k miles and immediately were getting upset with Honda about this issue. Honda initially replaced the tires upon this happening, but then changed how they handled it.

Now, all new NSX's come with a warning that the car goes through tires much more quickly because of the special alignment specifications that the car requires for such exceptional handling. Honda didn't try and change the car, just the explanation. People have to accept this as the price they pay to own this type of car.

I'm not trying to say that the 350Z is directly comparable to the NSX, but it's very similiar in nature. There are some sacrifices to be had to achieve superior handling. I'm not saying Nissan didn't make a mathematical mistake in the setup, they very well might have, but considering the price point and "fun" factor of this car, the tire issue really isn't that major. I think it's forgotten sometimes that this is a sportscar and isn't going to behave the same way as say a Nissan Sentra when it comes to wear factors such as tires.

 

Here is a link to one of many discussions on the NSX forum about tire wear:

NSX Prime discussion on tire wear

 

The Tire issue is old and tired. It can be fixed by an independant garge or service center.(not by Nissan) There are pleanty of kits out to change the camber etc......