I have 804S and 803D and find the smaller 804S almost as engaging. I think if both had the same crossover components, the differences might be even smaller. The 804S uses lower grade polypropylene couping caps to the midrange and tweeter, while the 803D uses Mundorf silver/Oil. I recently modded my 803Ds to Silver/gold/oil for both mid-range and tweeter and it makes quite a bit of difference. So I wonder what the 804S would sound like with those Mundorf silver/gold/oils and the upgraded resistors. Note also, that B&W used different series resistors on the tweeters to adjust the high frequency levels and this may impact how you hear them.
BW 800-805 D3 series VS 800-805 Nautilus/S series
I love the Nautilus and S series but hit a wall with the D series. At the end of my trials, the 800 N & S speakers always sounded more natural and right to me, personally. I have met others with this same opinion, surprisingly quite a few.
I'd like to know, if you share this sentiment, have you heard the D3 line? What are your opinions in comparison the the N & S series? Have they found their way back to the magic or not?