A friend runs his M60s with 93db, easily loading Silverline LaFolias and they sound great together. As others have said, a friendly impedance curve is quite important. Any >90db efficiency speaker that is mostly 8ohms or close will pair well.
IMHE, the Spletz Zeros add an audible whitish haze that detracts. I think that approach is like shoe-horning size 11 feet into size 10 shoes. After a while, it don't feel right! Cheers,
Spencer