^^ I thing the 89 octane here may relate better to 95 in Europe.
I found the fuel octane to make a big difference to me. On my epic trip from Utah to Houston, I was on 90 octane in new Mexico and Southern Colorado. Even with an octane booster the engine seemed sluggish. Outside Dallas (TX) I got my first chance at getting 93 octane. It made a big difference. The engine was purring and revving like a mofo.
That's the sad part of California - lovely roads to drive, fantastic cars, rich people but lousy fuel - can't get higher than 91 octane (US) there.
