I just followed the link someone posted in Phil's turbo thread about a wrx guy on nasioc who has been running an increasingly high mixture of e85 with gasoline in his wrx. Apparantly he has been running straight e85 for a while now with no ill effects. Without even having propper engine management ( he cleverly tricked his ecu into delivering the propper amount of fuel by putting in fuel injectors with a 25% higher flow rate) he's tearing it up and says that thanks to the performance improvements he only sees an 8% drop in mileage.
http://forums.nasioc.com/forums/showthread.php?t=803341