harry - I can address part of your query. The 2.2s were very well developed / mature and had a long run. Lots of fans. The 2.3s were the first application of the mechanical / crossover-less coax concept. I hear that there were improvements on the table pretty early, and not many 2.3s were sold, perhaps the shortest run ever. The 2.4 was a big uptick in performance and sales and has been an audiophile darling, possibly more so than any other Thiel product. That's some market mechanics.
Some folks here can address the sonic differences. I have and love my 2.2s and am working on a hotrod kit for them.
PS: I am calling the 2.2s by their proper name. The decimal was dropped under threat of lawsuit by Bose. But the product has been out of manufacture for way long, Mr. Bose is no longer with us, his legal staff was embarrassed . . . so let's pretend they don't care anymore.
Some folks here can address the sonic differences. I have and love my 2.2s and am working on a hotrod kit for them.
PS: I am calling the 2.2s by their proper name. The decimal was dropped under threat of lawsuit by Bose. But the product has been out of manufacture for way long, Mr. Bose is no longer with us, his legal staff was embarrassed . . . so let's pretend they don't care anymore.