This could be interesting.
As the Stihl MS500 has no carb what are the problems likely to be regarding ethanol based fuels?
You always hear ethanol problems related to carb powered machines.
Modern cars seem happy on ethanol based fuel and have been fuel injected for over 20 years.
Some very high powered supercars sometimes throw up a warning if you use inferior fuel but i think
this is more to do with using fuel with an insufficient octane rating.
As long as the pipes and tank hold up i dont see any problems during regular use