(Repost)From the Chief Technical Officer at Kodiak at Oshkosh2004:
There is not part of a rotax 900 series engine harmed by gasohol.
Gasohol is to be avoided in lycs and contis because they still use cork
gaskets which will dissolve. Aluminum is not effected by alcohol.
Water in alcohol may freeze at altitude.
Fuel hoses and o-rings in the Europa FirewallForward kit should
be checked separately for alcohol effect and replaced if needed with
Ira N224XS nearly 100hrs
There used to be an additive in gas to prevent water coming out of solution, probably benzene. No doubt some thing else now.