The only real leagal implications I see right off hand would depend on how much sipping... I mean testing you do, before you drive or try it out!
I had a friend who made his own... and ran a 50/50 mix... but this was in a mini bike.. and yes, he did his own testing, and fell off the thing now and then! Lol...
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.
i did some google searching, and you can make your own ethanol if you get a lisence from the ATF, denature it so it is poisonous, and report your production amount. also looks like it doesnt save that much unless you make a whole lot, but at least the money wont be going directly thru the oil companies.