the bolded statement isn't quite true... they are most certainly not all one company. they are all oil cmpanies, that drill for oil themselves.87. No point in anything else. I've run 89 and 93, no difference. The only time I ever noticed a difference is when I was in a bind and I had to throw in some Arco. Oh boy it would have been better to push the car. Ran like crap. It's never run right since and my mileage has gone from 32 down to 27. Of course around here, you have Arco, you have 76, you have Tesoro(if you can find one), and then the other stations, Shell, Texaco, and Chevron are all owned by the same company and all the gas is the same in them. Which is what I normally use. There is also Mobil stations but they are almost a dollar per gallon more then anywhere else.