If you can only choose one of these Amps

I've had a Classe CA 200 for about 6 maybe 7 years with no disire to move on, surround it with reference level components and cables and it gets better. The ca 200 doubles down to 400 at 4 ohms, I drive Thiel 3.6's to loud levels with no strain or congestion.

There is no clear spec for knowing how an amp handles a certain speaker. The relationship between power and current is Power = voltage * current, so it depends on the voltage which is where marketing comes in. How the power is measured is also dictated by marketing. All you can do is make a "rough" approximation of what an amp can do with the power rating. For your speaker specs, I would say look into 200W or more. How do you feel your ECI3 does - is it weak? Perhaps you don't need much power - depends on your preferred loudness level and room size too. Arthur

Like others I am not familar with all of the amps in your list, however I have very revealing speakers with a nominal impedence of 5 ohm and 86dba and I use a Muse 100 as my summer amp in leiu of 160wt tube monoblocks. Except for some loss of upper frequency air and extension I find it more than adequate, in fact it is the only reasonably priced SS amp I have enjoyed in my current system. The 160 Muse is an improvement over the 100 and at its typical used price I would give it strong recommendation for consideration.

The Muse 160. I have heard all of the ones you list, and chose the Muse. It was designed for unconditional stability into all speaker loads. A really good amp. (I have one that I have listed for sale, but I am its original owner and it's mint, and I think second owners in the current economy may have driven the market down to a price where I'd just as soon keep it. I was always ambivalent about letting it go anyway. You can probably find one for less from someone else.)

I have a fully upgraded McCormack DNA-1 Deluxe (drove it to Steve McCormack's house for the upgrade) which is just killer. I lived with the std DNA-1 Deluxe for 2 years with Apogee Centuar Majors, Audible Illusions Mod.3A, Linn LP-12, and Meridian 508.20 (pretty revealing). The update was well worth the $1200 (price from memory, might be wrong). The bass fundamental is rock solid and dynamic, the midrange and highs opened up even more. I've since picked up a pair of JM Labs Mezzo Utopias and Perpetual tech P1/P3 with Modwright 2. The McCormack still sings beautifully. You might check out a used McCormack 225 which might be cheaper than a DNA-1 Deluxe plus an upgrade.