There is no doubt that "synergy" is a real occurrence.
Go into any recording studio and you will find active monitors.
These are monitors with the amplifiers built-in, the theory being that you can design an amplifier to perfectly match your drivers.
That is what "synergy" is. Your given amplifier is designed to drive a certain type of load (i.e. the headphone drivers) and different drivers will match better to different amps.
As to burn-in. The article is...