I began my mileage hobby back around 1980, during the "energy crisis", when I was fortunate enough to get my hands on a 4-cyl Pinto
. It seemed like everything I did got me about a 2% gain: header & glass pack, water vapor, leaning the carb, new-fangled radial tires, etc. But when I put Amsoil synthetic in the engine, trannie and differential, I saw a 16% increase. Of couse, I don't see those gains now. With fwd, sealed CV joints, automatics, and manual tannies using ATF, only the engine remains to be syntheticized. (I love making up words)
I've also used synthetic grease on wheel bearings, and had a booger of a time getting them torqued correctly. I believe the reduced friction was leaving the bearings running cooler; hence they did not expand as much. I've heard similar stories from others using synthetic grease on bearings.
And when logging, I used synthetic engine oil on my chain. Though much thinner and less "clingy" than bar oil, the other guys were astonished at the lack of wear on my bar and chain. I'm sold on the friction reducing properties of synthetics. This is all anecdotal, but that's my opinion, and that's all I've got to say about Thayat.