I wonder what happens if you run the "racing fuel" setting with 91 oct fuel by mistake?

BTW: dealers might not be able to detect changes but Porsche is able to do that. It just takes a rep from Porsche with his little nice special version of the PST2 and you're busted. And there is even more to that...

So whoever wants to do such mods, feel free to do it but never think you can trick warranty. It may work, it may not. A new engine costs big money.