6.4 Hemi Trucks

Great info A body-One of my employe's has a 2013 with the def system and he is in the same boat as I am-Ready to get rid of it,He gets about 1 to 2 more miles to gallon than I do and really the def cost in my mind doesn't come into play,DO you know if the 6.4 requires premium gas ?????? if so then it really doesn't make sense for me to trade mine in,I don't get why dodge doesn't have flex fuel motors so a guy could use e85 if he wanted,Hell GM has had them for years and If i'm not mistaken ALL gm motors are now E85 capable --Steve