It can't hurt anything with the aforementioned additives for cheap insurance.
Having said that, I have been led to believe that ETHANOL of 10% or less won't damage your vehicle engine. On the other hand (on the other hand, I have warts) adding METHANOL certainly will damage lotsa parts unless they are protected.
METHANOL will definitely harm rubber and rubber type products and will attack metals that don't have a surface metal conversion process.
I have read that Brazil has a big ETHANOL industry derived from sugar cane and they fuel about half their autos with it.
I have also read that Australia uses a lot of METHANOL for auto fuel.
