I live on the Michigan border so it's easy to get fuel in the US. In Michigan 93 Octane is readily available at Shell or Sunoco but it's 10% ethanol. In Ontario (where I live) the best I can get is 91 Octane, no ethanol. My car is tuned for 91 but a safety factor is always nice to have. At the time that I got the tune, the tuner didn't have anything good to say about Michigan fuel.