E 85 (so far) is not cost effective. You get 30% lower fuel economy then gasoline as it has a lower specific heat. It is more expensive (and in all honesty with greed being what it is i dont think it will ever be cheaper) due to the costs of growing the material to make it. You need to replace all the ruber parts and possibly some plastic ones, and you need to have your tank cleaned. ALso since the engine will run cooler you may have a comfort issue in winter.
Unfortunitly Gasoline does everything well, from refining to storage to end use in comparison to E85 or any other man made fuel. I have seen black boxes to convert a car to e85, but they make no mention of rebuilding the fuel system, Buyer beware.
What everyone is misqouting (not here so far) is that it only costs 200.00 to convert a car to burn E85. That number is the cost on the production line, not after the car is already built.
Also the Ethanol mfg's are saying its not cost effective to convert an existing car.
http://www.siue.edu/ETHANOL/faq.html and
http://www.iogen.ca/company/faq/index.html(and found other sites that said the same thing). Surprisingly if you a carb its easier to convert then fuel injection.
Personally i like deisel or bio deisel, but no sooby deisel engine
nipper