I think the difference is the types of metals used in motorcycle engines and the tolerances they are built oto versus what they use in the vette engines.I did:
Dumped oil at 60 miles with regular petroleum based
Again at 700 miles with regular
Switched to full synthetic Repsol at 1800, and that's what I'll be sticking with.
Porsches and Vettes come from the factory with Mobil 1 sythetic, so I don't what to think about the whole break-in philosophy when it comes to that.