Glenmore,
I totally argree with your points! Well though out....
I use Amsoil 5-30, just because it's "technically" better. It would benefit me more if I didn't have a garage to store the LS.
If a dino user religously changes oil @ 3k interval = 10 changes for 30K miles
If a syn user changes oil @ 5K = 6 changes in 30 K miles
Therefore, it's only slightly more expensive to run synthetic in the auto....
Now, there have been tests on NYC cabs (typical RWD Fords). They've put whatever dino oil that was on sale in them and run for 6-7K between oil changes. Then compared to "by the book name brand' 3k interval oil changes... broke down the engines...and virtually NO difference in wear over extended period of time (about 50k miles ).
So, I suppose, dino oil will get you 250K no problem. My previous 2 honda accords got to that mark. The amsoil folks proudly claim you'll get 4-500K! But by then we'd could be spending 2K+ per year for other repairs - not worth it <_<
99