You're not supposed to make your own ethanol! That's the illegal part. The government has the legal right to take your house and all your property if you distill even one drop of alcohol.
But there's no problem with buying methanol or ethanol and mixing it with gas. (Gasahol)
Jetting and seal & hose material are about the only changes required, plus a change in plugs to a different heat range. I also believe the plugs erode faster, but don't hold me to that.
