bman, it depends on how far the MLP is, the sensitivity of the speakers, the room properties and the source material.

rrlev, with regard to the plastic inserts, I am referring to the terminals on the speakers. On the top of those terminals, there are holes that are exposed if you're not using banana jacks. My v2 had plastic caps that closed those holes.
A-LFR/1000-8 & 2/500v4x2
had v2;v4 FOC rock
Nx maybe