Thiel 2.3--bright or harsh ?

I think the problem is in your amp. My experience with a Thiel/Krell combination has not been good. I felt the sound was too harsh. I currently have a Thiel/Classe/Cardas combination which does not at all have any harshness to it. The Cardas Golden Cross cable are an excellent match for Thiel speakers. If you can afford them, The Cross model works well also. I have also heard McIntosh amps with the Thiel and think they have an outstanding sound.

I also upgraded my CS2.3 coaxial drivers. The new drivers are definitely not as bright. They are more laid back in the upper midrange and highs. Has anyone else upgraded? What did you think? Do you think the coaxial driver has overall design flaws?

I have to agree that Cardas cables are a good match for Thiels. I have a pair of 3.6's and auditioned several cables before deciding on Cardas. I've also found that my Thiels are very placement sensitive. Moving them even very slightly produces noticable changes in their sound. Mine took quite a bit of patience to get them positioned right. Having said all that, I've never been happy with their sound when listening to poorly recorded material. They seem to be very unforgiving in that respect.