Originally Posted by Saintor
87 is Ok on turbo DI Hyundai and Ford.
However, there is no reason not to follow BMW specs and they don't want 87 on N54/55.
Yeah, that's a good point: having a turbo doesn't necessarily mean 87 is out. But at the same time, Hyundai specifically targets 87 fuel in their engineering because they know their customer base will be into that. A supercar, on the other hand, can tighten up the engine and get the extra performance out of it, knowing that their customers won't care about being legitimately required to feed it more expensive gas.
It's like the AA tune people love to get for their BMWs. You can reengineer the engine to get a little more performance at the expense of freedom of gas choice. But from the factory, even midrange BMW engines are designed to run on anything available in the US, given the assumption that customers will feed them 87 sometimes even if it's not optimal.