Rob from Thiel got back to me with a quote of $300. I have a lead on a NOS driver for the 3.5 for $225 which seemed high at first but now seems like a good deal if it is genuine.
In anticipation of replacing the Thiels I auditioned some Sinus Faber Olympica II's. They sounded a lot like my Thiels and not enough difference for me to sink $10,000 (new) or $6,800 (used). Into them. I'm not even sure I liked them more than the Thiels. I also listened to a friend's Quad 57's with custom woofers. I have heard these several times over the years and was just refreshing my memory to use them as a reference. To my surprise I actually prefer my 3.5's that I have paired with a Velodyne DD12 sub-woofer that cost more than I paid for the Thiels. The woofer setup got rid of a bump in the room/bass response that really cleaned up the midrange. This may be because I took the bass load off my ARC VT100 amp, or because I got rid of the Thiel equalizer, or because I got rid of the bump.
