True about power.You can use 40 watt tube of 100 watt SS with 805N now way you can do that above 804N.I sold Krell and B&W from'96 to 2001. (just before change to S/D series but not much difference on this issue).The 803/802's had close to 90 db stated efficiency at NOMINAL 8 ohm load.But during play a nasty impedance swing the B&W's could go down to a high 3 ohm load.They nee current.A good (not cheap receiver but I assume your not going to go below Rotel,Adcom.NAD etc and probably have better).I think in mid sized room having 200 watts is must.Never Always thought with original series that 803N was best value and now they have 803S (why anybody bough 804's I could never figure).But now you can get phenomenal 803D with better high end and as much bass do to extra driver as original 802.Was not a "deal" but well priced at $8K.Now at $9K or 803S at $6K well you'd be judge.Used 802N's are fine if you have space.But if using HQ sub in 5.1 I'd go 803S and if not 803D (used $5500-$6K) is a great speaker.IMHO.But 805 and REL is great combo.You get better imaging with it but 803/802 will give you much bigger deeper sound stage.
Cheers
Chazz
Cheers
Chazz