I have had three "matched" systems over the years. First was a Apt Holman pre and Apt 1 amp.... pretty good combo for a 17 year old kid..... next was a McIntosh C15 and 7100... again, not a bad system. Third was a brand new McCormack RLD 1 and DNA 125. The latter was oddly enough the worst "matching" of them all.
After about two years with the RLD 1 , I replaced it with a Conrad Johnson Classic 2SE. That combo sounded great. For what ever reason I could not warm up to the RLD 1 . It wasn't bad but it didn't wow me like the CJ in that system.
The McCormack was sold and replaced with a pair or Quicksilver Mid Monos . A fantastic pairing that. I have enjoyed for about 8 years.
With respect to system synergy.... you don't know ya got it, til ya got it.
I'm still using the Quicksilvers, but now driving them witha Zesto Leto. The Leto is incredible, it also demonstrated how great sounding the Quicksilvers are.
Those 2 components have synergy in spades. Im having a 300b amp built, hopefully it will play nice with the Zesto.