Well, I simply replaced the mains with the MWT and didn't so anything else, like rerun Audyssey. The bass the MWT puts out is crazy,especially when standing in the hallway leading to the rest of the house about 30 feet from the left speaker. Afterward, I did run Audyssey to see how it wanted to set it up, and it reported the MWT as being large, confirming what I had been hearing.
Anyway, since then, I have picked up a pair of Wyred.4 sound monoblocks to drive them with that are a few years old. They seem to be a very good pairing.