The difference in octane is most likely a placebo to u. Although every car can adjust for timing mostly either neutral or retard timing. If u get crappy gas and causes the car to knock then your ecu will retard the timing and make the car feel slower. Theoretically, if you constantly got crappy gas then the ecu will always retard the timing and the car will always feel slow and under power. This will then be come the "normal". And when given better gas the ecu will set the timing back to whatever it was programed at neutral. Making the car faster than what you would be used to. In this case, faster is relative or in relation to using ****ty gas and not an actually increase in power or more than 148 hp.