I can't find that CR article on gas comparisons. I looked in the 2007 CR Buying Guide. I do seem to remember that article. That may have been a 2004 or 2005 issue. Shell may have been a poor gas back then. Remember when shell started all the TV ads telling how great there new gas was, higher mileage and a clean engine. That must have been their move to get on the top-tier gas list. Here in south I remember most of the Texaco stations being changed over to Shell.

Another low priced economy gas was Phillips 66. A few years ago they did a complete turn around. They added the extra additives to bring their gas up to top-tier quality. I have used it for a few years now, once they started stating there gas that can clean your engine's injectors and valves. My '03 Corolla averaged 40.5 combined mpg. Straight highway at 60 miles per hour with air conditioner my best was 45 mpg using phillips 86 octane. It's 4400 foot elevation here in the high desert.
I live 85 miles north of El Paso,Texas. Here in this town there are 5 new phillips 66 stations. Five new Conoco stations have been added this last year. Some of those were Exxon stations that are now Conoco.. My TCH came with a tank of Conoco in it and it ran fine. I have not talked to the Phillips tank truck driver as yet.

I would like to try Shell but their driveway here in town is not very level.

I don't understand why Exxon don't join the top-tier list.