You are about to get some sound advice, in my humble opinion (pun only partially intended), but this advice is only for the case where you go with ST amps. My first dealer told me that there was special synergy between the Bryston ST series amps and the fairly modest ($1,700 list price) Audio Research solid-state (MOSFET, actually) LS-3 preamp. On his advice and my ears, I bought a 4B-ST and the LS-3. Eight years later, I have owned Jadis, CAT, Hovland and Rowland Coherence II preamps, the latter now anchoring my main system. But the LS-3 is still in my second system (with Rowland Model 6 monoblocks). The LS-3 truly sounded GREAT with the Bryston 4B-ST. In fact, at one point, I was running the LS-3 and Bryston with $10,000 worth of Kimber Select all-silver IC's and speaker cables -- it was only at that point that I heard just how good those components sound together. So my advice to you is to buy a clean used LS-3 (they only cost $600 used) before you drop big money on something else. Make sure you keep it powered up 24/7. Run your best source component through the "Direct" input on the LS-3 ("direct" is a hot-rodded input that only passes through the gain stages and volume control). I do not think you will be anything less than thrilled. I've had a lot of different systems and believe that synergy is 9/10ths of the game -- your question suggests that you appreciate synergy as well -- try the LS-3 if you buy ST amps.
This advice is for the ST amps only. If you do the SST amps, you're on your own!
Good luck.