My review of the Spatial M3 Turbo S open baffle speaker is finally live...

@mapman Nice to hear from you again, old friend. :-)
I've had conversations with Clayton about amplification options. He has a partnership with Vinnie Rossi, whose LIO modular integrated amps he really likes and admires. But those seem to cost $5000 and up, and I don't have that much to spend.
On the Spatial forum on AudioCircle.com, several folks recommend the combo integrated amp/DAC line from Nuprime. These are Class a on the input side and Class D on the output side. Some people seem to love them, others a consider them to be rather "dry" and the lean. I've also heard wonderful things about a the amps from Odyssey, so I am looking into that as well. 

The two best Spatial combos I heard while I was part of the Canadian distribution was an 8 watt 300B based Finale SET integrated and an Ear 868 preamp with a Nord One Up Hypex NC500 Class D amp. Both had their own qualities and I can’t say one was better than the other. I most often demoed M4 Turbos with a Rogue Cronus Magnum II but stuck to solid state (MOON, Naim, Bryston) demos with M3’s. One great thing about them is you can try a variety of amps and the results are generally positive. 

Great review, thanks.

I stopped to visit Clayton's production facility in September which is in an industrial park about 10 minutes from the Salt Lake airport (4220 W 2100 S Unit L).  At this location, they have an inventory of transducers, frames, crossovers, etc. and several people hand building loudspeakers.  They also have an area, maybe 12x18 that opens into the assembly area where M3s or M4s are set up and can be played through the Rossi equipment.  The listening set up is nowhere near ideal but the sound was really good neverthess.  I emailed Clayton in advance and then called him a couple days ahead of time just to make sure he would be there...he was and we spent about 2 hours talking and listening.  My suggestion is if you are going to go, make sure to contact him in advance as I'm guessing he isn't stocking all of his finished speakers such as the X1 or X2 which are most likely built to order.