I am interested in this as I have been running on an E10 mix for a number of years and haven't as yet had any problems. (car does very little mileage these days) I am assuming this is the cause of the fires I have seen (on facebook) where the fuel has leaked on to the distributor.
In answer to your question, our fuel here is generally 91 or 95 octane (RON) and some years ago one brand brought out a 98 octane but it has quite a price loading on top of 95. These are all regular fuel with no Ethanol. I have been under the impression for many years (can't remember why) that my car is tuned (currently stage 1 chip) for 97 octane. Another company (GULL) came onto the market, and they sell 91 (normal) and 98 (10% Ethanol). Although dearer than 95, it is not as expensive as the standard 98 octane fuel, and as said, I have been running on it for a number of years. What should I be looking for to tell if it has deteriorated any of my fuel lines. Or is it a case of at some time they just start leaking. Interestingly, quite recently, another company has entered the market, that has 91, 95 and 100 RON, and definitely says on the website that the 100 contains NO Ethanol.
https://www.npd.co.nz/100plus-high-o...l/#toggle-id-9
David