I have told people many times they can run E85 without tuning...
Get 42# injectors... put E85 in = run great on a BONE STOCK tune.... It really is a flawless method and very safe. As long as you are running at least 70% ethonol in the tank (which can be done without much issues even with 3 gallons of regular in the tank), you will be more than fine to start beating on it quite soon.