Thiel Owners

Unsound - 2 ohm loads suck and amps give up. Thanks.

Jay - The CS2 2 and 2.3 represent a major tide change. The 2 2 uses all discrete Thiel-designed x Vifa manufactured drivers. They are conventional as single-band (woofer, mid, tweeter), although unconventional via Thiel underhung motors, copper motor shunts and so forth. The woofer is the first dual cone (straight-deep x curved-shallow). PP woofer and midrange x Aluminum (CS5) tweeter. The 2 2 was also the first passive radiator which became the new order. That basketless foam core diaphragm sported dual rubber surrounds (front and back of baffle) to maintain linearity without the cost of supporting framework. That geometry convinced Jim to migrate from the (very inexpensive) port to a passive radiator. In many ways the 2 2 represented a coming of age foundational product with seminal technologies.
The CS2.3 is a breakthrough to the coaxial-coincident upper driver. A central problem of first order slopes is driver lobing which makes listener position quite critical in the vertical dimension. (All those Stereophile graphs at 48" to eventually 80" misrepresent the integrated waveform at any correct (more than 8') position at the proper height (34" to 38".) You get the idea; lots of constraints. A coincident upper driver makes those upper integration problems go away, and the mid to woofer transition has long enough wavelengths to minimize actual mis-performance. The 2.3 coax incorporated the breakthrough viscous suspension which eliminated the electrical upper crossover, which could have been further refined over time to become a permanent solution. (Jim dreamed of a triax for true point-source propagation.)
However, as first-generation, the 2.3 coax was not mature. The product had the weakest sales of the series 2 generations with a life-span of less than 5 years against 9 for the 2 2 and 8 for the 2.4. The 2.3 was a watershed / breakthrough product introducing technologies that were improved by its successor . . . the CS2.4 became an audiophile darling. 

On a personal note, I was part of 2 2 development; the 2.3 was finalized after my time and its particulars are what I have gathered second-hand.

i thought the 2.4's were fantastic and were a big improvement over the 2.2's.   but every time i moved up (2.0, 2.2, 2.4, 2.7) in the 2 series the changes were always dramatic. 

The drivers became more rigid, operating more smoothly over a wider band-pass and therefore the compensation networks became fewer and simpler.

I would have thought the extra compensation networks needed for the older drivers would have driven the impedance down, yet the older models had easier impedances.