I've been running E30-E40 mixtures for about a year and a half now with various tunes (JB4 and now Cobb) without issues. I have thrown 29F3 which is the low pressure fuel sensor code for the longest time, but I am not positive if it was due to ethanol or not. I replaced the sensor and everything has been golden with no issues related to ethanol in my system.
Oh and my car goes like stink too!
