We all know that the specified octane rating for JKs (2015 +-) is 87. Youi can get by at lower octane, say 85, at higher altitudes. I never drive below 3,500' and wondered whether folks in similar areas routinely run 85. Locally, regular gas is rated 87 in the summer and 85 in winter, so it makes a difference only part of the year. The difference is $0.10/gal, so it's not a big deal, and I realize that Jeep may not leave room for common sense when it comes to fuel grades. Plus, nobody want to do any harm to their outfits.