Thiel cs2.3

The Bryston 4B is not rated into 2 Ohms. The earlier version's measurements show that rather than increasing it's power output into 2 Ohms it loses power output.
Bryston 4B power amplifier Measurements | Stereophile.com

^Hegel doesn’t spec their amps below 8 Ohms. Typically if a manufacturer can deliver the appropriate power output into lower impedances they’ll brag about it.

@nmmmusicman, The Vandersteen Quatro's are a very different speaker load than the Thiel CS 2.3'.:

Vandersteen Audio Quatro loudspeaker Measurements | Stereophile.com

Unlike the Vandy Quatro's the CS 2.3's don't come with a built in 250 Watt amp to take care of the heavy lifting. The CS 2.3's are recommended to be used with a minimum of 100 Watts per channel of amplification. The CS 2.3's impedance dips to 2 ohms, stays below 4 Ohms for most of the time, and has a high capacitive phase angle. The Vandersteen Quatro's briefly dip to 7.6 Ohms, stays above 8 Ohms the complete rest of the time, and has a low electrical phase angle. The Aleph 3 can't double down it's 30 Watts per channel into 8 Ohms down into the 120 Watts into 2 Ohms asked of it with the corresponding reduction in sensitivity into the 2 Ohm load of the Thiel CS.2.3's. Stereophile  (probably as an act of mercy)  only tested the Aleph 3 into a 2 Ohm load into 1 channel where it barely increased it's 30 Watt 8 Ohm rating to 39.1 Watts.  Keep in mind that the minimum power recommendation  for the CS 2.3's would have been the equivalent of 400 Watts into 2 Ohms. These speakers present very different loads to an amplifier. 
 I'm not sure where your quote comes from, but when one describes an amplifier as being stable into a given load; all they are saying is that the amplifier won't go into oscillations at that load, not how much power it produces, how it sounds doings so, or what levels of distortion it resorts to in order to comply with that criterion.
 Yes, "Not everything can be derived from measurements....", but some measurements can reliably provide, consistently predictive results.    
 

The Pass Labs Aleph 3 is not an ideal candidate for amplifying the Thiel Cs 2.3's.:
Thiel CS2.3 Loudspeaker Specifications | Stereophile.com
Thiel CS2.3 Loudspeaker Measurements | Stereophile.com
Pass Labs Aleph 3 power amplifier Measurements | Stereophile.com

^Good choice, but it appears as is often the case Class A output decreases as power increases into lower impedances.

Here you go:

https://www.youtube.com/watch?v=PEcFkSQMc8g

 I'm not sure why he thinks it's a rant, or how starting his speaker company is going to change things. 
 His points are right on target. And he gives a fair appraisal of the virtues of some of the renowned speakers that fall into the category of low impedance loads. He's correct that the standard spec has changed, and that it is now more complicated for the consumer.
 On the other hand the current spec is more accurate as speakers have typically never had a static impedance, and it really isn't too difficult for the consumer to calculate what amplification is appropriate so long as they know the minimum impedance. And while it's true that amplifiers tend to distort less into higher impedances, it's also true that amps and speakers prefer to work with more linear impedances, and that can be done by lowering the impedance but not by raising it. Furthermore, amplifiers that double down, or halve up with impedance do so with concurrent sensitivity changes, and therefore are better at maintaining frequency linearity. Also lower impedances are more immune to noise infiltration. Originally replacing larger speakers with smaller ones and replacing less powerful amps with more powerful amps allowed for more domestic acceptance of hifi. Now with home theatre and surround sound it's even appreciated more.   

Thanks,🙄 i searched and found nothing one those specifics.

^link?

They are.

^They have that reputation. The models with autoformers are somewhat unique, could be an issue with the CS 2.3’s rising impedance at the bass frequencies.

When a manufacturer claims that their amp is “stable” into a given impedance; all they are saying is that the amp won’t go into oscillation into that impedance, it doesn’t suggest how much power, distortion, or quality will be delivered into that impedance. Don’t assume the amp is truly capable of performing appropriately into a given impedance, unless they spec it as such. If the amp can deliver the goods; the manufacturer will brag about it.