Well bob the answer to that question is yes and no. There are many differnet formulations with different additives that the companies try to use to differentiate but for the most part are not that much different.

There is haowever the requirements that many different states apply to the gas sold in thier state that require different formulations that can be sold almost literally right next to each other- CA is the one with the most specific regulations but there are a large number of states including many on the East coast that require special formulations.

Bottom line though I guess they can't be all that different because you don't read about PA cars breaking down in MA because of the gas you put into them.

Dennis