GREAT discussion here !! -and very civil too !! -GOOD JOB, everyone
-and a good bit of research too, I'd say.
Here is a tiny tidbit: I think you will find that what started the whole Corvette/Mobil 1 deal was very simply this: Engine Oil Temperature. The design/application was resulting in oil temperatures that were getting uncomfortably high, and for some reason (-I don't remember just now) the engineering folks didn't (or couldn't?) go the oil cooler route, and chose to go with synthetic oil instead, which dropped the oil temps back down to acceptable levels. -check it out.
So, as I see it, GM essentially HAD to recommend synthetic for the 'vette.
As for the 3800, you can look at it this way: GM has no reason to recommend the synthetic. Think about it. (besides, there would be absolutely no cost/benefit reasons for GM to recommend it for applications that already will run a couple hundred thousand miles when properly serviced)
But, you can bet your "dog gone booties" I'll be using synthetic in EVERY 4-stroke motor I will ever own. (-and have, for at least 20 years)
Also, for me personally, the "pumpability" factor is a very important factor up here in our cold winters.
Say, "ejecto" You & I are certainly on the same page on this topic. I think you said it very well
GOOD discussion EVERYONE
--facts emerging,,,,,, myths fading,,,,,,