So I scanned through the E85 sticky but didnt really find my answer while doing it. Im getting two tunes next week, one for E85 and the other for 91. This may be a stupid question, but how simple is it to change between the two fuels? I dont mean flashing the appropriate maps from the AP, but when refueling the car. Can you just run your tank really low on one and fill up with the other, or does it require the tank to be drained? Sorry if the answer is posted and I just didnt find it, but thanks for any info!!