You did not mention the year.. Most cars that are 2000 & up are desinged to run on regular unleaded.. However it varies,, and some might run better on mid oct..
the one that gets you the best mileage... all gas is not the same nor is the cars or drivers but drive is the one who has to test a few brands to know which the car want to run best off of only way of knowing is by trying a type and marking down the miles you get .. best if you start with place you like to stop at most fill up with their best set the mileage or write it down drive til you need to buy again then fill with next type... you will find one that gets you a better mileage... then you go to another place you stop at every once in a while and do the same... its like my nissan gets good fuel mileage with shell high octane but it also gets the same with mobil regular you as driver has to do the checking to find which one the car runs best on
