Check out the Stickies for details. Some are running very low amount of E85 and have done little to their car and have gotten away with it. Just be sure your stock fuel system is in top-notch condition. As a minimum, I would drop the tank and be sure the sock is in good condition and upgrade the fuel pump. Also, run hot wire to the fuel pump so you get full voltage to it. Of course, your injectors must be clean and in great condition. You have changed your fuel filter haven't you! Would be wise to change it again after running E85 for a while since it will clean out your fuel tank, lines, etc.
If you go to high % E85, you will need a bigger fuel pump, fuel lines (?), fuel filter, and injectors. Your fuel system will have to supply 30% more fuel and, if you turn up the boost, somewhat more pressure. Be sure your fuel system is capable of handling the extra load! Oh yes, you will need a E85 chip or FAST or ????
Conrad
Hot Air