I think a Rotel Class D amp would be a great choice. They match well with B&Ws, particularly the 800 series, and have very small footprints comparatively, and run cool, so you can fit them in a cabinet without worrying about any over-heating issues.
The RB-1552 may be a good choice, but only runs 120 watts per channel. From my experience, the 800 series usually runs better with loads of power. The Rotel RB-1092 fits that description though a bit more expensive than the 1552. It's probably more wattage than the 804S needs, though it never hurts to have more headroom!
The RB-1552 may be a good choice, but only runs 120 watts per channel. From my experience, the 800 series usually runs better with loads of power. The Rotel RB-1092 fits that description though a bit more expensive than the 1552. It's probably more wattage than the 804S needs, though it never hurts to have more headroom!