When I converted to E85 almost 3 years ago now all I did was wack a bigger fuel pump and injectors in, fill the tank, tune it up (in summer) and away I went.
Only issue I have is cold starts as it was tuned on a 30 degree day. It took about 5 go's to start this morning.
I've been racing it with the occasional street cruise so the car can sit for up to a month at a time without an issue.
I know this is stupid but I still haven't changed the fuel filter since converting yet it hasn't given me any trouble. I've got a new one sitting there but I can't get the old one out...