Originally Posted By: PeterChenoweth
In my area, the common grade choices are 87, 89, and 93. Sometimes 92, very rarely 94. Thus, most of the time I go with 93. Not because 93 is better than 91, but because it's the only choice for my cars.


You may already know this (in any case, others may not), but if your car requires 91 octane, and all you have to choose between is 89 and 93, you can mix grades: half a fill of 89 and half of 93, and the mix will be 91. Could save you a little $.