Do you belong more to souce first or to speakers first school of thought ?

It is not a matter of debate. The room dictates speakers to some degree and the interface between the two makes up 99% of the sound quality the system is capable of. Next is the amp which has to be matched to the loudspeakers. Everything else is trivial. 

@hilde45 I hope that is tongue in cheek. 

I have one non-negotiable.  SET.  So amp first, then speakers to match.  The source is fungible.

Speakers first then an amp to match.

Speaker synergy with amp is the 1st step in creating a HEA audio system. Preamp over source. I know this might upset vintage or budget conscious buyers but when you skimp on electronics, speakers and source components can not reach full potential.

No one remembers Ivor Tiefenbrun, founder of Linn, "Garbage in, garbage out"?  You can't improve what you don't get/can't get rid of any added distortions from what comes off the record, cd etc.  I've found that as I've upgraded my source, I get more of the artist's intentions, lyrics, instrumental lines, etc.  Of course electronics, cables, speakers, room matter, but you have to start with a high quality source.