I currently buy 91 octane-non ethanol fuel for my boats, even though my engines are rated for 87 octane. I just want to avoid the ethanol. This seems to work fine and I will continue to do this if necessary. Here is my question... Can I add a product such as Stabil Marine fuel additive to 87 octane E10 fuel and be secure in the performance. If I read the info on the Stabil Marine formula it sounds like that is just what its for. The Stabil would add maybe 10 cents a gallon, but that is still cheaper than buying premium, and the premium non ethanol fuel is not as readily available. What do you think?