Looking for a SS Amp to power Spatial Audio X-5's

@fixedincome, 
Your speakers with 97 db sensitivity,  8 ohm impedance and built in powered subwoofer  allow the option of pursuing/focusing on  watt quality more so the watt quantity. In addition to the excellent suggestions for the Valvet Audio  and First Watt S,I.T.-3 also look at the Bakoon Audio 13R. BTW there's also the First Watt F7 and F8 to consider. 

A very high quality lower watt  power amplifier should work exceptionally well with those Spatial Audio speakers. Best of luck.
Charles 

@mikem,
Congratulations on acquiring the S.I.T.-3 you’re  off to a very good start straight out of the shipping box😀. I’m looking forward to your amplifier comparison.
Charles

You might want to ask the question also over on AudioCircle, where there are quite a lot of Spatial owners.

If I remember correctly, Spatials often like a bit more power than what their sensitivity might suggest they need.  Therefore the Pass XA25 would be a solid suggestion.

Thanks all!  You gave me some ideas to start with.  I'm looking at the Chore Ultima series partly because I'm hoping for a good blend with my Dave DAC.  First time I've heard the term "Watt Quality."  I assume you mean the stableness of the flow (Watt is a Watt, unit of measure).

@fixedincome - yes, a watt is a fixed unit of measurement.  However, a high quality 20w amp that suits your tastes will sound a lot better than a poorly constructed 100w amp that doesn't suit your tastes.  In addition, the way an amp clips can make a big difference to the perceived quality.  Tube amps generally create pleasing distortion when they clip whereas solid state amps tend to sound harsh when they clip.