Re: A couple points ...
Octane doesn't do what you think it does. Octane ratings tend to be like trouser snake measuring contests. People see that some exotic sports car needs insanely high octane and conclude that if they put higher octane go juice in their grocery getter it somehow gains performance.
One exception: on a modern high-performance engine, performance will be reduced by the engine computer to compensate for use of fuel with lower than recommended octane levels.
Octane just makes it harder for the fuel to go "boom" before it's supposed to. Put low octane fuel in a high-compression ratio engine and it starts to turn into a diesel. The compression starts igniting the fuel-air mixture before the spark does, which is a problem if the piston is still on its way up.