[JAR0023]

OP I agree with you to a point. Your SC manual was accurate when written. Porsche has issued tech bulletins changing their recommended oil weights and change intervals.

No doubt our cars need an oil with an additive pack friendly to flat tappet cams. Long time ago there where lots of them. Then the manufacturers all started pulling zinc and phosphorus levels down into the danger zone to extend cat life. Engines died because of this and at some point the oil companies listened to the market place. First it was specialty oils and now most of the bigs have some flavor of oil with the right amounts of zinc and phosphorus.

Synthetic oils hold up better under extreme heat. Do you and I need to run synthetic, not likely a need unless we are racing or live in an extreme hot environment.

I fell off the Mobile 1 bandwagon some time ago, but recently jumped back on it, at least for my wife's car. It's the only M-B approved oil I can buy locally. It's actually pretty cheap and I can get it at W-M. M-B says I can go 15k between oil changes. That's just too long for me without some oil analysis. For about the same cost I can put new oil in at 7500 and feel safe and M-B will never know.

I run Rotella Dino 15-40 in my 911. Good base stock, good additive package with plenty of zinc and phosphorus. Can be bought at just about any FLAPS or truck stop out on the road. My personal experience leads me to believe I burn less between oil changes than with one of the other special grail oils.

My point in all this rambling is there are bad oils out there that will kill your Porsche engine. There are also plenty of good quality oils that work just fine even though they aren't as sexy as the boutique brands. -J