here is a nice discussion comparing the 803S to the 804S. I know that you did not ask for this but this discussion reveals several characteristics of the 803S that might interest you. Also, several posters did a comparison with the 803D version & have compared/contrasted the 2 speakers. I think that it might worth your time to read these posts:
http://www.avsforum.com/avs-vb/showthread.php?t=736201The N802 is a very good speaker & I would say that it is 1 notch below the best of the Nautilus series speakers of that era (which was the N800 even tho' there was the N801 which had the 15" woofer. The 15" woofer made it impractical in 99% of the homes as it would overload the room severely & make listening impossible). The N802 speaker is not to be underestimated in terms of your amp's ability to drive it. If you do get the N802 you'll probably have to change out your amp to ensure that you can drive it correctly & optimally to get the best from it; otherwise, you'll be wasting your money. The N802 *demands* the very best electronics if you want to hear what it can do (a good friend of mine has these speaker & he + I have been around the corner or two coaxing the best out of his speaker so I know what I'm talking about + I've owned B&Ws myself). If you are not ready to overhaul your system to upgrade to the N802 buy a more modest B&W like the N803 or N804 - you'll get much better sound for less cash outlay. My assumption here is that you are not made of money; in case you are, disregard my comments completely.
FWIW.