Originally Posted By: Kuato
I did a test on our two Jeeps several years ago with ST Syn, and the UOA came out great at a 5k interval; just as good as Amsoil, M1 or VWB, just a little less additive in the ST compared to the other synthetics.
That is because there is not a whole lot of difference between the oils these days. Syns may last longer than GPII etc but in respective classes of oils nope not much difference. They keeps the parts from separated and where they can't the additives do their thing etc.