Good to know that the Spendors don't overpower the room. Actually I would not expect that in a room of your size. And I completely know what you mean by the "deeper, fast and tight" bass. Having heard the Spendor D7 and owning the ProAc D48 I can completely appreciate it.
Furnishing seems to help the cause of taming the bass and overall sound. But what amazes me is the fact that you are very happy using the XA30.8 over the X250.8. I would have thought that you would give up "dynamics", "soundstage" and "drive" when moving to the smaller amp. You retained all that when driving the D9s with the XA30.8? Amazing!
Yeah, looks like the Steve Blinn company is no more. BTW, I also like the color of that room.