I'm not going to say its true or not but there is some hardcore Chevy guys down the road from me that will never use it again. They do local drag races, build motors, paint cars, etc... I talked to the owner and he swears royal purple ruined two of his motors. One was a big block.
I cant understand why oil companies cant just make a non-syn oil like they did back in the old days when oil was absolutely full of zinc and not charge a arm and leg.