Ron: I've spoken to an ESSO rep here in Canada. She told me that the superflo oils are PAO based. Also, on the Imperial oil Website, it states this as well. I too was looking for a PAO based alternative to the new M1 at the time, but now I'm thinking about sticking to M1, as I find it hard to believe that a company such as Mobil would want to jeopardize their repatation with a shoddy product.