[JRinKY]

I have run regular, plus, and premium in my NA, and cannot tell any difference in driveability. I have not detected any knock or ping. I have recorded effectively identical fuel mileage with each grade. Using my G-Tech I have measured apparent engine power and gotten virtually the same reading with each grade of fuel.

As near as I can tell, for the conditions in my area, and using Chevron fuel, there is no advantage to using premium.