"So the differences all comes from the beginning"
If you are a bass head, drive with many subwoofers.
Of course, science is a good support. How else to find out what is appropriate? That and the experiences that follow from it. You saw for yourself the calculator for suitable (sufficient) power amplifiers, as well as how to take the dynamics of the music into account. How else would you figure it out? Test lots of amplifiers, unnecessarily?
Another example, measurements. How good modern DACs are, learn where the limit for the audible is, so you do not have to put any major money on DAC. Such a thing, about DAC, never appears on forums that address Hifi from a purely subjective point of view.
Then as I believe in principle everyone says: The powder should, as usual, be placed on the speakers (and EQ).
EQ subwoffer you will not get around.