I put stabil in my cars that sit for extended periods of time, no problems with fuel going bad so far.

I know my 300D runs WAY better on Cetane booster now that they took the sulfur out of diesel, but that doesn't answer your question.

AFAIK all gasoline is a minimum of like 2% Ethanol now, so it's unavoidable. I'm not sure what additive is going to help you. If you have water in your tank run some like ISO-Heet or similar to pull the water out of the fuel.