Ctsooner, I hate to disagree with you but I must. All systems are NOT synergistic.
We have seen way better results in some instances of using a tube preamp with a solid state amp sometimes from different companies.
We have also seen that sometimes too much of one companies products can tilt the sound in an unfavorable way while in some instances company A's amp plus company A's preamp does indeed sound better.
As per synergy you would think in our main demo rig that the T+A preamp, plus the T+A amp, plus the T+A reference SACD/CD/Dac would sound the best, after all they are all from the same company and were designed together, yet the Davinci still sounds signigantly better.
So if your point was valid then the all T+A system should sound way better yet it doesn't.
In your case Vandy Treo and Vandy Quattro are voiced similarily same with your friends B&W, if you for example moved from Vandy to Magico, or Vandy to Rockport, or Vandy to Rahido you would probably not be digging the combo with Ayre.
The Vandy/Ayre combo works at the Vandy's tend to be a bit on the overally warm side with the Ayre's being a bit lean. So the combo works beautifully which is the defination of synergy.
We tried many brands of expensive reference gear because they did not work well with some of our speakers. For example we tried the Thrax gear which was fantastic stuff, and CJ, and Devialet and none sounded as good as the T+A gear on both our Polymer speakers as well as the Personas.
When we had the Scaenas the CJ combo was magical and sounded better then our reference solid state Chord stuff at that time.
So synergy is when you find a set of speakers, electronics, digital, cables power conditioning etc that work together to create a sound that you find that works to your particular taste and sonic expectations.
The main reason for why so many people flip their gear is they do not know how to create synergy, when sometimes just changing cables or adding a few things can make a system come alive.
Troy and Dave
Audio Doctor