Jap cars are designed to run on 100RON. However, it's a bit too expensive and inconvenient for me so I'm living with 98 RON.
Ethanol is a solvent, rather than corrosive. Petrol is a solvent as well, in many ways. Ethanol is probably a bit more aggressive which is why some people are worried about rubber fuel lines etc.
That said, Sydneykid has been running an ethanol mix in his skyline for years and regularly cuts open his fuel filters to inspect them, and has never seen any evidence of a problem. That's good enough for me.