My friend has a pair, very nice but very hard to drive to their full potential. You need big S/S amps with good current with BJT outputs (no Mosfets), IE: amps that almost keep doubling their wattage with each halving of loads 8ohms to 4ohms to 2ohms.
He has also already pulled them apart and fixed a few small phase problems they have in the xover design, which you or I wouldn’t even notice, and B&W didn’t bother with as it added many more components. But he is a measurement freak, and wanted to fix that up, and he said they sound even better now, on or off axis.
Ooops sorry his were the 800 D2