My uneducated two cents worth.
You probably get more bang for the buck mixing a quart of synthetic with three of dino vs. buying a blend that's only 10% syn.
Since Mobil 1 Drive Clean's a group I oil, Pennzoil is probably just as compatable with Mobil 1 as it is and probably a better oil for the money IMHO.
We're all getting carried away with this stuff anyway. I've owned approximately two dozen cars over the years, plus three bikes. Had exactly three engine failures for the lot. One was a Corvair (nuff said), the other two were Mitsubishi engines: one lost coolant and I cooked it, the other was the infamous Mitsu 3 liter V6 valve guide eater. Since the transmission was toast at 100K, it wasn't worth putting in valve guides. Many of the others went way over 100K with little if any worry. Most that died, went to the big reward for other causes than engine problems.
[ March 25, 2003, 03:16 PM: Message edited by: csandste ]