Any oil that claims it clings to parts uses ester. Synerlec from Royal Purple is marketed to do the same thing. Magnatec and Synerlec are might be the same additives for all we know.
Nope Synerlec is a sulfur compound, has acidification issue and wont meet API certs.
Look at old RP VOA and the astounding PPM Sulfur in the oils with synerlec.
Starbust RP look just like the old, inexpensive NAPA Synthetic
Though they may have JUST changed the formulation .
Loved Magnatec 0w20. Price was good and it was what I started with on my car 300,000 miles ago. Granted I moved on since then but for daily driving and stop and go ruitine ; this is the oil. Someone on this board got to speak to someone who knew alot about Magnatec from Castrol. Their 0w20 is their unicorn with only group 3 & 5.