What is the general consensus on using synthetic oil in an old 200-series oil-cooled turbo? Mobil 1 seems to be "the stuff" around here, but I can't see throwing away that kind of money every 3000mi. The owner's manual recommends changing the earl 'n filter every 3500mi for the turbo engine (b21ft). Is it OK to change at 5000mi intervals or greater if you run a syn oil? Does Mobil 1 come in 20w50? All I've seen on the shelves at the local Checker's are 10-30 and 10-40 weights. Doesn't ever get cold enough here in No. California that I would need that kind of protection.

Also, why does there seem to be this general bias on the BB against Fram, Pennzoil, etc. filters? I've been told to use Mann filters if I'm really serious about maintenance, but these damn things are smaller than the original Volvo OEM filter, and smaller still than the equiv. Fram part I can get at Checker's. How can the filtering area possibly be 10% greater as IPD claims??