My exhaust tips show different amounts of soot. I clean them off and the same thing happens. Porsche service said nothing wrong with engine. They're good at what they do; I trust them. However I did not get a definitive answer ast to why the soot is different on each side.

Somebody at Porsche Central Command knows why this is happening. How to I get to them? Must I become insistent to my dealer/service people?

BTW, I'm thinking there's a problem with the cooling system. Maybe one side is running colder than the other. A blockage? A defectibe thermostat?

Sorry, but I just can't relax and drive with soot-wierdness just because the Porsche service diagnostics says the engine is okay.