I seem to remember a STP bottle saying it had twice the PTFE concentration as SLICK50.
I also remember my first introduction to Slick50 was similar to the Amsoil approach for dealers, actually a little worse, they actually went door to door trying to sell it. I think that was like 1980. I thought it had died, next thing I know they were selling it in stores in 1990+.
I guess the science of particle size and ring/cylinder wear just isn't communicated.
Every time I saw an oil burner on the street, I wondered if they had dumped this stuff in the oil for the last few years.
It absolutely blows my mind that Quaker State sees some value in keeping the name alive. Every time I see the combo pack of new formula Slick50 and 4 quarts of Quacker (sic) State I want to gag.