I was on another board yesterday and the owner had posted the latest article on the new Mazda engine. Well the conversation immediately went to fuel economy and how the new ICE motors are quickly gaining on the Hybrids and this isn't a good trend for the BEV's, especially Tesla. Anyways I brought up what I had learned from Wayne with his experience with Shell and how advanced the Top Tier gasoline's are today, and how they DO help you increase your fuel mileage. I explained my experience with switching over to Shell exclusively. I got the all gasoline comes out of the same refinery with a splash of additives there isn't any difference between Top Tier and non top tier. The guy I'm having this conversation with has an MBA and has owned business's in the internet and software domains. He's a very smart guy there's no doubt about that. There was a point I didn't want to go past because all it would do was annoy the guy and nothing I could say was going to change his mind. Anyways, I decided to prove to myself that I was right today and took the 2010 Prius out for a drive. 70,250 miles, Defender tires, 44F-42R all stock and I'm running as I said Shell 87 exclusively. Went out for lunch and a three hour tour on the interstate. I set the cruise control to 55 mph, turned on the AC and just enjoyed the ride. 61.3 mpg for the day with no Hypermileing techniques applied. That 61.3 mpg proved to me, that there is a difference between various gasoline brands.