Subwoofer shopping...

Hello gentleman....
This is my first post and hope some of you have some good insight. First my system consists of the following:
A/V receiver: Integra 50.3
Pioneer Elite: BDP62FD
Front and rear speakers: Paradigm Studio 20
Center channel: Paradigm CC490
Subwoofer: Golden Ear Force Field 4

Attached is my room layout with fronts, rears and center channel noted. The scale is one square equals 1 foot so interpreting relationships is possible. Currently the GE (Golden Ear) is in front of the fire place and I'm just not getting the base I want.
Let me describe the room characteristics. Behind the sofa, the entire wall is mirror. To the left of the sofa is all glass with plastic verticle blinds. The living area is sunken by 2 feet (10 foot ceiling). The remainder has an 8 foot ceiling. I know its a challenging room for acoustics but where the main speakers are located is about the best I have found through trial and error. The GE sub is located in front of the fireplace firing toward the sofa. Oh, and there is a coffee table in front of the sofa that is basicly a solid wood rectangle.
I currently have a REL T9 on order should be in in a week or so I was going to put where the GE is (fron of the fireplace) and relocate the GE behind the sofa (firing accross basicly creating a sound traugh) moved from the wall about a foot. Another location would be to the left of the the sofa firing accross the listeners feet.
One consideration is replacing the GE with a Pardigm Seismic 110. I listenned to it at my local dealer and boy is it powerful! The decision for the REL T9 is for its musicality. It will be connected to the high level outputs of the A/V receiver where the sub will be connected via LFE.
I would like opinions and suggestions regarding my selection of the REL T9, selling the GE and replacing it with the Seismic 110 and any other suggestions regarding placement etc.....

Thank you all who respond in advance...

Room layout.JPG 1014k .JPG file

My intention for the REL is for its musicality. I could cancel my order for the REL if I had a change of heart but so far I am not convinced there is a better sub at the same price point for music since it blends seamlessly with the front two channels. It's intended location was is on the floor in front of the fireplace however I tried the GE Force Field 4 there and the base didnt have much impact. This morning I moved it behind the TV about 8" from the back wall and 20" from the left wall (window with vertical blinds). Put Battleship in the BR player and it sounds MUCH better.
I just put a call into David at Rythmik and sent him an email with a copy of my room layout to discuss a E15HP thinking this would be an improvement over my old Velodyne FSR15 and of course the GE Force Field 4 will be gone too. WHat I want is to not only hear the explosions but feel them too. When I heard the Paradigm Seismic 110 w/ 850w RMS amp at my local dealer it had what I was looking for however its only a 10" driver as opposed to the Rythmik with a 15" w/ a 600w amp. One of my questions, IS it 600w RMS?
Oh, and I'm not sure where the Rythmic will be located in the room yet. Possible locations would be to the left and front of the sofa firing accross the room or next to the sofa opposing the TV either side firing forward or behind the TV where the GE F4 is now firing toward the sofa. Another thought was to put the sub on the elevated level of the room either to the left of the sofa or 8 feet from the back wall on the same level. I hope this is all clear...

I had this whole reply typed out and the website decided to do maintanence so I lost it... Lol
Ok here's an update. First to answer the previous questions. My movie to music ration is about 80% movies and 20% music. The Rel arrived yesterday and I placed it in the corner behind the left front speaker pointing in the direction bisecting the corner angle. Was an interesting thing tuning it. As per the manufacturers direction, I turned the crossover to the lowest frequency and turned the volume up so its volume was matching the front speakers as close as I could get it. Then adjusted the crossover to where it sounded best. Funny thing as I adjusted the volume I could hear the base compression in my ears such as in the heartbeat of Pink Floyd's Dark Side Of The Moon. The I lowered the subs vloume till the compression in my ears went away. The volume was about tiny 3 clicks from zero. Then I tried every possible location (mentioned earlier) to locate the Golden Ear. Behind the sofa was just too much and you could hear where it was comming from and sure made the room smaller moving the sofa away from the wall. When I located it on the bedroom level firing towards the windows to the left of the sofa, it turned the other part of the house behind it into a wonderful base tunnel but near the window was kind of empty. To either side of the sofa firing forward didn'nt work either since there was base in that area but the opposing side was empty. The only place that worked was in front of the fireplace. The fireplace harth is just a few inches taller than the GE so it has a corner its resting in there. Refer to the drawing. It makes a good compliment there..