Coincident speakers 14 Ohms - What amplification to use when streaming Tidal.

are there speaker at 107? Probably.

Such will be horn-loaded. The Hartstfield loudspeaker, which uses JBL components, is quite respected and is 105dB.

97 (or even 94) dB sensitivity is VERY efficient.

I would characterize 97 as the high end of moderate efficiency and 94 in the median of moderate, with 90 at the bottom. 89dB this at the higher end of low efficiency, and 97-98dB at the lower end of higher efficiency as there are speakers that are 107dB 1 watt/1meter...

My Coincidents are at a 97 db sensitivity, so I don’t think that is inefficient, but what do I know.  Seriously, using an 8 Ohm amp on these 14 Ohm speakers will cause what kinds of problems?

Yes- at that impedance 97 dB would be a high sensitivity. In practice though it appears that the speaker is more like about 94. Using the 8 ohm tap will be no worries.

That amp would sound fine, but if you plan to fill 1000 sq feet(!) you'll need considerably more power unless you will be fairly close to the system.

The 14 ohms impedance isn't problematic for any amp.

It does not matter what source you use or what music you prefer. But you will need a bit of power since your music room is a bit bigger. So the SET idea is right out (and FWIW, most of the Coincident line is a bit on the low side efficiency-wise to really show off most SETs). The speakers are an ideal match with our M-60s, but they are outside of the stated budget. For that sort of money I'd be looking at something used with at least 60 watts.