Yep, makes no difference in "normal" cars.

Engineering-wise the compression ratio of the engine is the governing factor for power and fuel requirements. S2000 US cars run about 11.0:1 with some JDM cars maybe 11.1:1 giving a tiny power increase. Running low octane fuel in a high compression engine is inefficient because of pre-detonation (knock) but modern ECUs and knock sensors will normally protect the engine. Conversely running high octane fuel in a low compression engine does nothing as the compression isn't high enough to cause knock to begin with and that's all a higher octane prevents. I suspect the low power readings in the video tests are the result of the ECU and knock sensors retarding the timing. Cars run better on the fuel for which they were designed.

But the 'placebo' effect remains. And there may be some dishonesty with some cars. Guys who pay a lot for a car may expect it needs "premium" fuel. We all know it doesn't hurt anything but our wallets. I think my Alfa Romeo had a Shell gas sticker next to the fuel filler. Ran fine on supermarket gas with the right octane.

-- Chuck