Thiel Cs 2.3 with neodium Tweeter of CS 2.4

It's quite likely that it would necessitate a cross-over change.

As unsound said, above. You'd need to have the TS parametres of both tweeters, which are probably unobtainium.

Best to check with Madisound , maybe someone has checked this out!

You can contact this guy that used to work at Thiel and still does some repairs. 
https://www.coherentsourceservice.com

pivz57

Phil- if interested, consult Mr. Rob Gillum at Coherent Source Service (CSS) as above. Feel free to join us over on the Thiel Owners thread as well.

I look forward in reading more about your Musical tastes and system.

Happy Listening!

Just sell your 2.3s and buy used 2.4s.  Not worth the headache of trying to get the 2.3s to sound right, and sadly the company’s no longer around to advise you.  I’d personally explore other brands as who knows how long parts will be available for Thiels.  Vandersteen, ProAc, Joseph Audio, Usher, all excellent imaging/Soundstage speakers on the level of Thiel IMHO and all still solvent.  

Thank you all for your responses. I have to explain myself.

I love my Thiel CS 2.3. Truly. I have had many speakers in my life, these are among my favorites.
My problem is that one of them suffered a very bad fall because of a child. The woofer and the tweeter are badly damaged.
I contacted Mr Gillum who offered to redo my tweeter. I found an OEM Boomer in Germany. However, and this is my real problem (don't laugh) I AM FRENCH

Between the cost of the repair, the cost of transport, the cost of customs, the price of the OEM woofer, I'm not far from buying myself a new pair...

A person sells a pair of CS 2.4 tweeters not too far from my house, and since they have the same shape (but not the same magnet) I wondered if the modification was possible..

Now, if that can't be done I will have to find an alternative solution.

If you know someone selling a cs 2.3 tweeter... I might be interested too.

Anyway, thank you all for your help, it's super nice

Cut your losses and get some new speakers, preferably from a brand that is still in business.

There is a Thiel Owners thread on this forum. I would suggest searching for that thread and then posting your question there. A few members have rebuilt their crossovers and someone may have experience that will be useful.

If I were in your situation I would probably buy the pair of 2.4 tweeters and go ahead and try them. Odds are they will fit and if you won't hurt anything if they aren't optimum. The CS 2.3 speakers are hard to beat for a reasonable price. I understand why you want to salvage them.

Thanks for sharing all that good info after the fact.  I’m out.  Good luck.