1: There really is a thing such as system synergy.....nice to read your post & read your realizations. I'm afraid that I have to disagree with your revelation of "system synergy" - there is no such thing as system synergy. Each & every audio component has to hold its own electrically & sonically in the overall system so that the grand total sounds fantastic. Electrically means that the input/output impedance of the unit has to be a correct electrical match to the other component upstream & to the component downstream. If this electrical interface is screwed up, you'll get screwed up sonics. Sonically means a whole host of things such as little or no global negative feedback, high quality signal capacitors, robust power supply (this itself is a loaded statement but I will not discuss any further here as I want to keep to my main point), chassis damping, segregation of analog & digital power supplies, local power supply decoupling & the list goes on.
It is my belief that you have stumbled upon "system synergy" because you have accidently put together a system that has the correct electrical interface more than any other parameter. It would be good if you realize this & understand why the electrical interface to each & every component is correct so that when you are ready to make a change in your gear you select another piece of audio gear that also has the same correct electrical interface.
Thanks.