I want to hear BlazerLt's thinking on this. It's interesting because if you go to
http://www.lubedev.com/ they sell oil testing equipment (BlazerLT can do that Lucas Gear Oil additive test). They promote doing all of your own testing and it seems like their articles are very informative, however they seem to blame the U.S's problems on foreign dependency of oil. He also says he got 30% better milage with Texaco gas- whatever.
I like how he pushes that you should do your own testing and verify his results, however I would like to see more information.