Aside from the (I believe) 100 octane "racing fuel" a buddy of mine once got, about all I've ever seen is 87, 89 and 91. Often, stations in San Antonio only have 87 and 91, with no middle grade.
Personally, although it's an SE, I've been using 89 octane (I try to use only Shell, as I consider it the best on sale here) in the Challenger. When my salesman and I were talking, I asked him about what fuel to use and he told me that although the car would run fine on regular, when Dodge does its fuel-economy ratings, they use 89 octane. I figure if it's good enough for Dodge, it's good enough for me.
