Hi 1985tqc, I own the Monolith 111's and have driven them with just about everything, big 150w monoblock push/pull UL pentodes, massive monoblock SE 805 DHT, big Mosfets.
While they worked with all of these still sounded good, it wasn't until I used a >150w bi-polar amp (big older Krell type)that can good great current that they came alive.
As for the Monolith 111 themselves, they are compromised in the bass, that Eminence driver they had made is not too good, doesn't go low enough and is a bit 1 note'ish and it's F/S is too high. I found a good sub that matched well to T/S parameters of the box was the old ACI SV12 this is a killer bass driver and suits well. Unfortunately it's no longer available it was too expensive to produce.
Here is a post I made on it.