From what I've seen with our equipment, the biggest missing link is smooth delivered bass, without taxing the smaller amps that the BnO equip. came with. IMHO, (this is what i did) get 1 or 2 powered subwoofers, get very good quality and drive them (it) off in the corner. This is easily done with either the attenuated RCA out or converting Powerlink to RCA's.
This really lets you drive the entire BnO components very light and the burden is placed on the amp in the sub.
I can't tell you what a difference it makes. I've got pentas, 8000's and 2 high quality 15" subs. I mostly use it for home theatre, but if i was doing this again and listening mostly to music i would have went with 12's not the 15's....they are just tighter for musical reproducition to me.