Thiel 2.3 vs 2.4 the real difference

In my own personal experience, side by side testing is sometimes not revealing of differences, unless you have first spent quite a bit of time listening to each of them on it's own. I don't know why. I assume it's because your ear somehow learns the character of each of the different speakers. It sounds like you have done that though.
Art

Art, I agree with what you said, but in my case I was intimately familiar with my 2.3s. But not with the dealer's (excellent) room and equipment. As the 2.4 is so similar, it was the differences to the well-known 2.3 that stood out pretty clearly. No doubt if I replaced the 2.3s with 2.4s in my own room & equipment, I'd hear a lot more of the subtleties between the two. But that wasn't an option at the time and I just don't think the differences are much more significant than what I heard in a different space.

Side by side is the only reliable way to tell minor differences. Our ability to remember subtle changes in sound is poor to say the least. Memory does funny things and is more affected by other stimuli than most would admit. Tests have shown people tend to find differences when no component had actually been switched. As for the Orions, I am still putting them together. The cabinetmaker left out the screws for the drivers and some pilot holes were misplaced and others missing altogether. Part and parcel with DIY stuff I guess.

Did anyone took the mid/tweeter driver out of the CS2.4? I am just curious if Thiel really make the drivers themselves as it is not viable to manufacture a relative small number themselves or, what I suspect, Thiel is installing a(n) (OEM) version of a known brand like SEAS or Dynaudio in the CS2.4

The rationale behind it is to get a cheap(er) CS2.3 and mount CS2.4 mid/tweeters.
There is a good reason that Thiel wouldnt sell the CS2.4 coaxial drivers by themselves or put them in a CS2.3

Thiel used to use outsourced drivers that were modified to Thiels specs. They've been using their own drivers for some time now. The most recent ones, such as those used on the 3.7's are clearly very different than those used by others.