congratulations on a great set of ears! speed of sound, 6 inches, that is bat-like. I went two weeks without noticing that one of my rear speakers was disconnected!
I can't think of much sound-wise that I would change, except maybe adding a second set of 7.1 analog inputs. It would also be nice if I could see the audio-mode better on the display. I guess all my enhancements would be age-related...