Here in Oz we have 91, 95, 98 I have used all and found no real difference.
So I stick with 91 and about every third fill use 95 or 98 just to make me feel better.
Low compression motors dont enjoy the benefit of high octane fuels. Higher compression motors benefit due to higher anti-knock ratings associated with higher octane ratings. 87 octane Pemex Baja cactus juice works fine in our motors. Its designed to.. I used to run bluegas in my blown 5 liter Stang and my Gixxers, but the motors were hi-comp or forced induction and thrived on it. but I also worked as an A&P on an airport and had free access to it. Dont run it in anything with a converter. Toast. Concerned about water and dirt from the bottom of storage tanks? Buy only at stations that sell high volume, their fuel isnt sitting around waiting to be sold. And buy only quality-Chevron or Shell. Just sayin'.....