There are so many variables in audio all interacting at the same time (including the interaction of the acoustic space (which can negate synergy of same brand mentality), that its a bit like a multitude of drugs interacting within the body ( substitute the body for the acoustic space). That's why high end audio is a crap shoot, an endless fascination/frustration that keeps most of us going in this hobby.
About synergy?
Many audiophiles believe in using cables and electronics as corrective devices. The other side thinks keep all your equipment with the same sonic flavor, otherwise you will more then likely end up with an audible mess. Some even think it's a given to match your source(cartridge/cd player)with the same sonics of your speakers. I stray slightly to the same sonics camp, but i'm very curious what others have to say about synergy.