What sub are you using?

Regarding the fullness of the M80s when set to large, I prefer mine set to small with a cross-over of 80Hz. I tried virtually all combinations and this is the one that sounded the most accurate. But I do agree that they sound more full when set to large. And this is due to the peak at about 70Hz to 80Hz on the frequency response graph. When we hear fullness, we have to ask ourselves what exactly in the source material is producing the fullness.

Regarding the low frequency thump, are you sure it's not 60Hz noise? Put your ear up to the sub with no source playing to see if you hear a hum. The source of the thump has nothing to do with hard surfaces.

As for the punch, do you have punch during movies but then seem to lack it for music? Maybe the fullness that you experience at higher settings isn't really supposed to be there (ie. it isn't musical). The previous sub I had was "full" but I realized after I got the EP600 that it simply wasn't natural. I can make my 600 sound that way too but I've learned that it's just wrong .

I tried my 600 in a corner facing into the room and into the wall. I didn't like it as I was getting too much booming. I moved it away from the corner and it became more musical but still shakes the foundations during movies.