Overkill for small room

I assumed I'd set up the speakers on the narrow end

I think that with your size room it would be better to place your speakers along the 11' wall. This will allow you to place both your speakers and your listening chair closer to the center of the room and away from the walls. You should try and keep a few feet if possible between your chair and the wall behind it.

The room will always be your biggest obstacle in achieving great sound. I would put most of my energy into learning how to either tune your room to your system (room treatments) or tune your system to your room (equalization) or a combination of both.

My room is 14' 4" x 10' 6" x 9'. I'm pairing small bookshelf speakers with 4) 12" subs. I play very loud aggressive music and I feel the highs are very clear and distinct, the mids are warm and natural and the lows thump but are not boomy.

continued excellent advice. I've got a lot to think about prior to the amp purchase, but the research and learning is a big part of the fun for me.  Thanks to all who have contributed helpful advice.

@audiorusty - I'm curious to know what you consider "very loud aggressive music." Do tell. And 4X 12" subs? What is your crossover? Are you feeding them with sub-outs or speaker-level? It must thump, indeed.

I’ve owned the special 40’s. They work quite well with Jazz, classical, and most vocal instrumentation. 
 

Electronic, rock, hip hop. Yes. They will play. Though they do not accelerate well with that style of music. At least that was my experience. Pass labs xa25, Herron vtsp line stage. I have zero treatment in my room, with the exception of wall to wall office carpet for my entire apartment. Maybe it helps. Maybe it hinders. Went back to my old speakers.  My little part of the world is good now. 

I heard the Dynaudio Special 40 with Moon electronics at Quintessence Audio in Chicago, and man that was some music/sound. Immediately grabbed my attention and I could not just NOT sit down and listen. That was some special pairing. But the room also made a big difference.

I'm curious to know what you consider "very loud aggressive music.

Lately I have been listening quite a bit to Fear Inoculum by Tool.  I also like Orbital, NIN, Ministry, Big Black, Moon Duo, The Black Angels, Foo Fighters just to name a very small sampling, along with other genres like Folk, Jazz and classic Country.

And 4X 12" subs? What is your crossover

My main speakers are book shelf speakers, so two of the subs are slightly behind but in line with those, and those subs are low passed at 161 Hz using a 24 db Butterworth slope while the mains are high passed at 191 Hz using a 24 db Link/Riley slope which gives me a 6 db down point a little under 200 Hz. The actual down point and frequency will vary somewhat depending on the gain settings for the front subs and mains which varies from recording to recording. The other two subs are placed in an asynchronous (not the word I want but the only one I can think of right now) pattern in the room and are high passed at 79 Hz using a 48 db Butterworth slope. All four subs are high passed at 34 Hz using a 24 db Butterworth slope.

Are you feeding them with sub-outs or speaker-level?

My preamp connects to a XTA DP448  speaker management unit that handles the crossover duties, time alignment, gain setting, driver protection, and per channel input and output equalization if desired. I will never again use a speaker level sub connection.