Do any cars require synthetic?

You bet!! Alot! My Carrera, C5 Vett, My LS-2 GTO...the list goes on! Most high end cars, whether it be sports cars or luxury, the manufacturer requires you use Syn. You could probably use non syn, and have no issues, but if you'd have a motor prob, and the warranty was in force, and they investigate......trouble could be on your horizon :(

That wasn't an error, PZ. I like my oil dirty. Like my women.

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Redline is fully synthetic ester based oil, that's what I run.

I didn't know that :tiphat:

Motol, Red Line, and Amesoil are the only ester based aftermarket oils that know of. with 5 quarts, a good filter, and 17bucks in labor at the quick change station makes for $100 oil change for me.

thought this article would be of interest here:

Oil Test

blackstone labs is a company that basically analyzes oil samples you give them. they also do radiator fluid and etc (if you're so inclined, or perhaps you have a leak). if you read their faq, some of the questions are "do you guys recommend any oils" and they all state they use dino. while I have no idea what they drive, they would know more.

I always debated with AMSOIL, Redline, Royal Purple, and Mobil 1 for what oils to use. I had to order my first oil change, which was Redline. Since Royal Purple is sold locally, I'm gonna change to that next oil change. If anything, for the sake of convenience. They have to do another bearing test like the above article (which I have seen thrown around many times on threads such as these) in a more modern setting.

Castrol 0-30 GC is a fully group IV oil. The rest of their "Syntec" line is not, however.