How does it speed cold flow when it won't even come out of the bottle when it's 30 degrees or less?
A very similar product, Schaeffer's Moly EP, made one of my tractors turn over much harder on cold days than with the same oil without the EP. It's thick, period.
As far as VSOT goes, maybe it does help with oxidation and breakdown...when added late to overextended drain intervals. If you look at the info, it says it resists breakdown and oxidation better than STP. Not good synthetic motor oil. As has been mentioned countless times, in good oil formulations, you probably aren't making the oil any better by adding VSOT. The research that has gone into making these formulations is complex and very balanced, and throwing additives in willy-nilly is, at best, a calculated risk. Will it hurt anything? Maybe not, but over the long haul, potentially. Will it help? Probably not.
I am sure that there are engines and turbos out there that can still lend themselves to this problem, but again, using excellent oil and draining it when it needs it (UOA) should prevent 99% of these problems. With sludge and coking, ARX is probably the best bet to clean it out safely, while preventing its return.
Triple Se7en is obviously a firm believer in this product, and that is fine. I have thought about using it myself in a couple select applications on older units that could benefit from the viscosity boost and added AW additives. I have ended up using Moly EP since I couldn't find VSOT locally. That said, IMHO, it is not the right product to fix/prevent the problem we are looking at.
It is my feeling that the inevitable shearing of the high concentration of long chain polymers could lead to sludge issues on long drain intervals, perhaps creating an environment ideal for some primo turbo coking. Also, the thought of all those thickeners sitting on the scorching hot turbo as it cools doesn't make me feel too great either. We all know what happens when they burn in the combustion chamber--they stick rings.
