What component is responsible for dynamics ?

amplifier(integrated or separates) in synergy with speaker considering that the placement is correct.

don't worry about tubes or solid states in the chain at all.

Agree that if you want the full range of dynamics, both macro and micro, highly efficient horn speakers are the way to go. This is one of their biggest advantages over other speaker types, and I want to emphasize that this is not just on the loud end of the spectrum, but the very soft end also.

this is a great question. the same should / could be asked about soundstage. I wish someone would answer it. There should be only one correct answer.

Rok ;
Yes one correct answer would be nice . But usually just a major consensus is the best that there is .

It depends on what you are currently using and your room. Without knowing the details, it is impossible to tell.