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^^^ Thats true but if your already running the correct octane petrol and not experiencing any knocking then using a higher octane petrol cant reduce whats not actually happening. To take advantage of higher octane petrol your ecu needs to be able to advance the ignition timing or your car needs to be retuned to accomodate the different AFR and ignition timing. Using higher octane petrol also lets you run a higher compression ratio.
I also hear that some engines are able to self adjust timing based on fuel... can it sense this :S?
Yeh IIRC most modern cars can advance the ignition timing slightly, i think they use the knock sensor to do it but not sure on that still a bit of an ecu noob :) They can also retard the timing if they recieve a bad batch of fuel or low octane fuel to help prevent knocking.
this is true, most cars for about the the last 10 years or so can tune to the fuel, using closed loop O2 sensors and knock sensors, the timing is continually being adjusted to the optimum. I have a Navara dual cab V6 (93) Monaro (2002) and civic (92) and all make more power and get better fuel economy on 98 (but i only use BP)