Used passives generally aren't worth much. Those are no exception.
They shouldn't sound "nice", they shouldn't sound like anything at all. Little hype for the sale maybe? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif Most decent manufacturers tailor their xover to the comp set being used, as each mid and tweeter will perform differently, interact differently, etc. You CAN use those with pretty much any speakers having the proper impedance (prolly 4ohms each), but its not gonna be ideal. Replacing the manufacturers passives with these on your Infinity comp set, for example, would more than likely decrease performance, not improve it.