I hear people have differing opinions of what gas to use in the OPEs. Some say you should use 89(Mid-grade) or the 91(premium grade) octane gas in them. I can agree with 89 or 91 in some two stroke engines but not an across the board recommendation. Most 4 stroke engines are designed to run on 87 octane. Straight gas is another recommendation. Either its the anti ethanol crowd or someone influence by the anti ethanol crowd that believe that. However, there is some merit to this especially to most 2 stroke engines or any older engine. Either of these option come with higher price tags. There is one I did think of and that is top tier gas. It usually has higher detergents and other stuff. And usually cost a tad more. What do you think of top tier gas as a good recommendation for OPEs?