I've heard about the gasoline coming from one refinery for different regions and everyone adding their mix of additives...but in the case of Quaker State, Pennzoil, Shell Oil...are they all using the same additive? I doubt shell would want to employ 3 different research and development teams as that would shave millions from their billions in profits. Also Shell as a parent company owns Jiffy Lube as its a division of Pennzoil, so Shell has alot of interest in motor oil and end clientele.....

__________________
My Cars
Mercedes CLS
Mercedes C-Class W203 - All time favorite

R.I.P.
Mercedes C-Class - W202 Lemon
Mercedes ML - Warrior
VW Jetta – Worst Car I ever owned - Alot of problems