But the computer can be reprogrammed in some cases and you can run E85 if you really wanted to. In others, the fuel rail, lines and pump has to be upgraded as well.
Not really. Injectors have to be larger, and safe with ethanol, and nearly all non flexfuel cars have fuel lines that would be reactive with the fuel as well. The pcm would in a lot of cases not work, as many of the cars have sensors to measure ethanol content. If you have a flexfuel car, great, run the stuff if you like, but if you don't, its not worth the time or hassle to try and make it work. I've had the joy of dealing with a few cars that had E85 pumped in instead 85 octane. Very obvious signs when looking at the data, including fuel trims pegged across the board. Never good to run an engine that lean. I did see where you made the note in vehicles so equipped Mark, but I just wanted to make a stronger point, as some would gloss over that and miss it completely is all.