30 years ago I didn’t even believe in synthetics, working at a parts store, until Valvoline introduced their DuraBlend oils, when I got to be thinking…….then when my buddy showed me his Polaris snowmobile engine since he used the Amsoil Saber 2 cycle oil and there was zero carbon buildup and the cleanest 2 cycle engine inside you’ve ever seen…..this was back when snowmobile manufacturers didn’t have a handle on 2 stroke emissions yet, so they all burned very dirty and left a lot of deposits behind, except those using Amsoil. Fast forward 5 years and I bought my first VW diesel, no oil company made a compatible 505.00 spec oil, so I was forced to choose a full synthetic motor oil, and 25 years later with 425k on my VW diesel it’s like new inside. And yes, being in the VW world all this time I’ve seen plenty of oils and what effect they have on an engine.