Fuel tank lining, fuel lines etc., although not sure how long it would have to sit w/ a high concentration to do any damage. I've just read to keep the % mixture below 30%, as stated. That, & the burn qualities are slightly different than pump gas.

I've also looked into running E85 (85% ethanol/15% gas) in my turbo'd vehicles, both for cost & octane reasons. However, the main issue w/ E85 is that you have to burn a whole lot more of it, & that affects your tune. It is also not recommended for long term use in vehicles not "E85-equipped," again I think due to the corrosive nature of it. My research indicated that to be safe, I would need to go through my whole fuel system, switching out the fuel lines, installing a pump that is alcohol-approved, & going w/ bigger injectors to handle the increased fuel requirements.

Her4Runner