Another oil debate.
Porsche did approve conventional mineral oils.
The latest leaky RMS theory is that the M96 motor was tested with conventional oil but when the vehicle went into production Porsche then said to use conventional or synthetic, but the car was filled at the factory with, guess what, synthetic.
So what did all the owners use? Synthetic. Wonder how much Mobil paid for that sticker, like they make the only synthetic oil in the world.