Amp & Speaker Synergy

Limo, you want an amp that can drive your speakers. If they go down to 1 ohm and are very inefficient you do not want to get a 3 watt SET amp.
You will need a solid state bruiser for that. If they are very efficient horn speakers like Klipsh Heresy's then you can use just about anything. Then if you prefer the sound of tubes go for it. Then there is how loud you like to play. More volume means more power. Again, how much depends on the efficiency of your speakers. Then of course there is the issue of how much you want to spend. 

With speakers I eliminate anything under about 90 dB. This avoids being screwed into having limited amp selection. Nothing worse than having to look for a really good 300 watt amp. Because there are none. That cost less than a house I mean. 

Then since I didn't screw up on speakers I only need an amp with a good 20 watts or so, and now I can focus on whatever amp sounds the best. There are a now a huge number of truly awesome amps to choose from, without even cracking $5k. (See: Raven Nighthawk.)

All this business of synergy, matching, its all BS. A good amp sounds good, period. But the myth goes on wandering the land like a zombie because, well for a lot of reasons, few of which are actual reasons, but there you go.

The last, last, LAST thing you should ever do is buy something with a known flaw just to try and patch up a flaw somewhere else. Which is exactly what is meant by matching, synergy, etc. All flowery phrases used because system matching sounds better than band-aid slapping.

Having heard the Fritz Carrera's driven by a Modwright 300B headphone amp at CAF, we know it doesn't necessarily need a lot of power, and that tubes are OK.  But that doesn't necessary mean that that is the direction to go it.  A bit more power might be even better.  I know what you're getting at, but honestly I think it's more just a question of good synergy between the two components, on both the technical plane and the more intangible sonic one.  The answer would be different of course, if the speaker were in the very low or very high sensitivity brackets.