I use Fleetguard (Cummins), Baldwin, Racor, CAT, Amsoil, AC Delco, NAPA Gold, Wix, most of which are synthetic or synthetic blend elements. My applications are light trucks, oil and diesel fuel filters. I do not use Fram cardboard or private branded filters that do not have published specifications. Any of the top line filters are more than adequate. Filters are just not a major cost item, but injectors and bearings are, so a quality filter is not a waste of money.