Newbee makes a good point regarding the way the two speakers will respond in-room.
Having owned both the 6381 and now the 6371's..I found that my room was better suited for the 71's.
The 81 is a very good speaker, but requires a fairly large room to properly place them. In my 19x22x8 room, and at a rather near field of 10 ft., they seemed to overwhelm the room with bass, and I used a variety of different SS and tube designs and varied sources. Additionally, the lower 8" driver didn't seem to seamlessly blend at that distance.
the 6371 to my ears is a more seamless and coherent sound that has a tighter bass presentation, without sacrificing the deep bass.
I think if your room is a medium size or what you would not concider "large" in space..you may be better off with the 71's performance.
You will want to bring them out from the front wall a minimum of 3-4 ft if you have the room to do so. A modest toe-in will give great imaging and a fuller, textural body to the mids and lower mids.
If you can't move the coffee table as you mentioned, it will not help eithers speakers performance of course, but Id look at room size and placement first in deciding on which model to use.
