I currently own 803 D2 now as my main speaker and am familiar with the B&W soundstage presentation as far as D2's go. I've not yet been put off by its more intimate listening experience but the D3 did seem even more intimate which is why it's hard for me to say if that little bit of extra intimacy will be tiresome in the long run. To be fair, the 803 D3 when I heard them were litteraly just out of the boxes they shipped in so break in had not yet occurred.
In any case, I now have more Magcio questions
Has anyone had success using a JL Sub in combo with their fast Magico's?
In terms of amp power requirements, I've heard that the S3 can be powered by as little as 50w as long as the amp is rated to output high currents and handle lower then normal impedances. With that said, I believe I have this part covered already and would intend to, at least initially, use my Hypex NC400 mono blocs to power the S3's. The amps are good for 24amps of current and output 400w into 4ohms with a rating of just about 575w into 2ohms all with extremely low distortion, a basically non existent noise floor and are neutral to a fault. Seems like a good pairing for a speaker like the S3 but my only fear is that all this neutrality could make for a boring and lifeless sounding system compared to a more "colorful" speaker like the B&W. I guess only time will tell on this one.
Thanks again for your thoughts.