I take the Denso, and like the other guy said the first time fit has the siicon adbv, and they claim 2 ply media. The fit and finish is very good, with a plastic cover over the end to keep dirt away during storage. If they do that,they care. As for the 51% efficiency, that is all based on one test from Amsoil I believe. If I see two more impartial tests, preferably not from Amsoil, with like results, I will believe it. Maybe even one more, but not just one from Amsoil who have a case to make for theirt business.
The other point is the issue of how many times oil circulates, even on a short trip,discussed on this forum, renders the efficiency rating to the back burner, way back, IMO.