Kwik Trip 91 octane ethanol free. I get better fuel economy and it's roughly $0.40 cheaper than 93 octane 10% ethanol in my area. I'm tuned but I just chose to use the 91 octane tune to use this fuel. Cenex also offers ethanol free 91 octane and is a chain of gas stations owned by United Cooperative and is one of the best locations for ethanol blending pumps, but isn't as readily available as Kwik Trip. Kwik Trip is basically a religion in the state of Wisconsin. Not many use premium here, but a lot of toys and small equipment call for ethanol free, which is why I think KT has decided to offer it as their premium option.