Mobil 1 Synthetic 0W-40. You can get it at Porsche and Mercedes dealers, but also, surprisingly, at Saab dealers. I went to the Saab dealer as it's much closer for me, and the parts guy was willing to give me a discount on a bulk purchase.
Quote: 2easy said: Howdy - about to buy a couple of quarts for my 997 C4S - what brand do you use / tips can anybody offer? Just head down to the dealer?
Mobil 1 0W-40 is what the decal says under the hood. You can usually find it at AutoZone.
Try to find the 5W Mobil One that's recommended (allowed).
The 0W stuff is recommended so the cars get better gas mileage (good for environment); the compromise is the engine wears out a little bit sooner.
Seriously.
Also, just use Mobil One. Do NOT experiment with other brands. There's a lot to why they recommend it. FWIW, If I did not use a specific Castrol oil in my 04 M3 the warrenty would have been voided.