Pass labs xa25 amp and BW 804 d3?

I know pass equipment and their Class A amps are quite powerful.
It should drive the B and Ws easily and sound very smooth and detailed.
If your room is really large and you need additional volume go to one of their Class A/B amps to get the extra power.  

As I said, I know Pass overbuilds his amps, and you might not have any issues, but once again, why tempt fate?
If it were me, I'd take the safe route and get a higher powered amp. I believe in having lots of headroom when it comes to power.
 Then if you decide to change speakers,you'll have a wider range to choose from.
I see some XA-30's for sale that are under $5K, still low, but closer to recommended specs. There are a pair of XA-100's, asking $6.5K though, but would be a real killer.
There are other manufacturers, but I don't know if Pass is the only one you'll consider.
Bob

Gweedoargus,
You have gotten some good responses and comments. I’m inclined to agree with those who have raised the very important consideration of ’sound quality ’ as compared to increased quantity (higher oower/more watts). The Pass Labs XA 25 is capable of 50 watts of pure class A into a 4 ohm load (this isn’t an insignificant amount). It can provide class AB 200 watts maximum into a 2 ohm load (This is impressive).

The John Curl designed Parasound A21 offers class AB 250 watts into 8 ohms and 400 watts into 4 ohms. So clearly higher power. I suspect it has pretty decent sound quality. Keep in my its DF (Damping factor) is >1100!! This suggests very heavy use of NFB. Some very respected amplifier builders such as Atmaspere and Roger Modjeski consider this amount of DF gratuitous and without meaningful benefit. On the other hand some builders (John Curl I’m sure) would beg to differ. My gut feeling is that the Pass XA 25 could very well be the superior sounding amplifier.

Is there the interest/desire to home audition these amplifiers and actually hear them driving your B&W speakers? I would bet that the vast majority of your listening the XAX25 would remain in class A operation. This is a good thing IMHO. I'm expressing my own biases. I don't believe in the cliche of "the more power the better" once you have sufficient power the objective should be placed on quality. 
Good luck,
Charles