Yeah ethanol is sketchy if you haven't modified fuel delivery to handle the stuff and it will affect tuning without rejetting the carb to run on it. I've gotten into the habit of adding synthetic 2 stroke oil to my DD with premium fuel (95+) It runs like a top - I'm only using 100mL for every 10 L of fuel but not on every tank (maybe every second/third refuel...) The fuel stabiliser is a good idea if you drive your car only once every few weeks.