Just thought I'd briefly post that my EP-600 showed up yesterday. I haven't had a lot of time to play with it yet. My (wife's) first realization was that it didn't look good where I'd planned to put it under the screen, so it quickly got moved to the back of the room. However, in our 12x20x9 room, it really doesn't seem to make a huge difference (from very brief testing), and I will begrudgingly admit that it does look better back there (don't let my secret out).
I did run it through the Denon's auto-setup routine this morning only to have it return that my SW needed to be set at -12db in the receiver's EQ (the lowest it can go). This was fairly amusing as the gain dial was set to 9 o'clock (barely on). With my last sub I had the gain close to maxed and the EQ between +9 and +12 depending on the source.
So, in terms of headroom, I have undoubtedly taken a huge step up. I played the Darla fishbowl scene in Finding Nemo this morning just to amuse myself and was quite pleasantly engrossed in gut wrenching bass. I also was introduced to several rattles in my new home that I didn't know about. The springs in all of the windows are apparently not at all soundproofed.
Musical tests later this weekend. I need to do a more thorough calibration of my HT that involves an SPL meter but have been waiting for the EP-600 to arrive. Hopefully within a couple of weeks I can get my hands on a meter and do some more tweaking.