I wonder if this "bulletproofness" would have anything to do with the status of the car model. In their first 10 years they were luxury sports cars with a high price tag probably regularly maintained by authorized shops. The next ten years continued as cult legends, maintained by owners like us with a passion and overcautious schedules like oil change every 3k miles etc.

Would this 'marketplace' not likely have a more preserving effect on our cars as compared to many other makes used more as a way of transportation - no special care or passion involved ?

Just a random thought.

Will I be banned now ?

I think this is the most likely reason. Plus maybe other engine refinements over the earlier 70s cars. And the reputation for engine longevity.

I have Randy Leffingwell's "911 Buyer's Guide." He talks about the new alternator/voltage regulator being a problem in 1982-89 cars. Says they only last about 40K miles. Symptoms of failure, he says, are power surges to headlamps, battery, or a/c air blower.
I've noticed my a/c air blower , which I use w/o freon just for fresh air thru center vents,does increase (then decrease) speed by itself periodically--and wonder if that is the weak alternator symptom Randy is talking about? A mechanic I talked to doesn't think so.

I have an '82 with 90K miles that is a very tight machine. It looks like a machine, and feels like one. The torque maxes at 4000 rpm , which is ideal for tooling around country roads at 40 mph or so. You can go by a cop having fun in 1st and 2nd, and he doesn't blink. Above 60 on the highway in 5th, it quiets down--and gets quieter as you increase speed. My 300Z used to do that, too. But the SC is so much tighter. Amazing for a 24 yo old car. They are built like a Rolex.

>He talks about the new alternator/voltage regulator being a problem in 1982-89 cars. Says they only last about 40K miles

Wow ! Mine lasted 170000 miles so far ;-)