Interesting... I had a 98 Boxster, and the engine blew at 34k miles after the warranty was out. Replacement with a new factory engine was $12.5k, used was 6k. My Porsche dealer aftermarket warranty would only cover a used engine of the same year (and presumably same problems). I wanted a new engine, and ended up wrangling with the regional manager for Porsche for a couple weeks. After being a pain in the rear, Porsche agreed to cough up an extra 5k, with me contributing 1.5k for the new engine. I thought was an OK deal, and that in the end Porsche treated me right. However as soon the warranty was up (it was a 1 yr warranty), I traded the car straightway for an Infiniti sedan - faster and more powerful with almost as good handling. Now at 90k + miles it has had 0 issues and drives as new.
I swore I would never by another Porsche, but am thinking of a 996 now... would you buy one without a warranty?
I have had my 2002 Porsche Turbo for almost two years now without any issues, save for vibration at high speeds. I am taking it to Eurowerk Houston to check out this October.
The other issue which just cropped up is when the car is started, sometimes the A/C compressor, wiper and Xenon headlights would not come on.
Besides the above, the car has been fine.
Update February 2012:
It turned out the wheels were bent. This has now being fixed, but I still noticed some form of vibration now at higher speeds.. 130mph+.
Also replaced the key starter, and that fixed the A/C compressor etc issues