Thank you guys: appreciate your additional feedback; I do respect your opinions but eventually it was comes down to personal sonic perceptions, preferences and esthetics - the latter cannot be underestimated as a factor for people not having the luxury of dedicated listening rooms.
Having said that, I was very keen on getting the S400 but decided to abort. The big issue for me was their size - seeting them and hearing them live (a step above, at least to my ears, my current N-sats), they are enormous and this SADLY makes them incompatible with my extremely limited space for placement, i.e. very close to rear wall with minimal space for adjustments. The room would have looked properly cluttered and unsightly to all but me...; but most importantly, the sonics would have been comprimized and the S400 sub-optimally utilized.
Next step is to explore Wilson Benesch down-firing models such as Trinity, Vertex and potentially, the Discovery (original model). Vertex can be auditioned locally which is an advantage, in addition, both the Trinity and Vertex look quite similar to my N-Sats. Will update in a few months following research and auditions. Enjoy the weekend, Vik