Been using synthetic (Mobil1) in my 951 exclusively and wouldn't go back to petrol-based if you paid me. Now, with the new 0-W40 and 0-W50 spec syns my coefficient of friction at cold start is near 0%, and my effective oil weight protection is either 40 or 50 at operating temp. At my next scheduled change I'm going to try Royal Purple syn in the 0-W50 variety.

Seems if the shop charged you $5.50 a quart for oil you got the Castrol Syntec -- unless the bastards are charging those prices for regular oil.

If that's the case -- Starmark or not -- I'd go elsewhere in a freakin' hurry.

- Fred