Thiel Owners

Andy - I second your motion. As car guys say, the least expensive option is the one you have. So if you have 2.4s, then upgrading resistors and caps is a huge bang for the buck.

It's just so happen that my current car is a 2004 model so I would agree :-).  

Beetle - a 3.7 upgrade is quite straightforward since the drivers are so well behaved, there is not much circuitry in there. The tweeter caps could be upgraded to CSAs with perhaps an ultra bypass around the 1uF styrene/tin. Electrolytics to film for permanence. Resistors to Mills MRAs. Film feed coil on the woofer. More upgrade for less cost than the more complex 2.4.

You'll see more from me after the Thiel Audio bankruptcy settles.

Tom

Regarding bass extension: I own the 3.7s and 2.2s. The 3.7s have been in my system ever since buying them last year and I'm preparing to sell the 2.2s.  I was noticing some "crackle" in the tweeter of one of the 3.7 speakers and decided to change out the 3.7 for the 2.2 in an effort to narrow down the problem. Turns out I had a frayed speaker cable. Here's the thing. My perception was that the 2.2 actually offered more realistic bass extension. I had one of the Bach cantatas on for reference. Bach uses just one contrabass, but it needs to be heard. I felt the 2.2 did this better. But, the overall texture of the recording was much better with the 3.7. I could hear the lute in the ensemble readily for instance. That was not so clear with the same selection rendered on the 2.2. Totally nuts, or what?
Todd

More upgrade for less cost than the more complex 2.4. 

The coax has separate XO for tweeter and midrange, right? Ie, not mechanical like the 2.4.

is this pic for all 3 drivers? Or just the coax?
https://hi-fi.com.pl/images/numeryhfim/2012-03/jpg/44-50_03_2012_07.jpg

Stereophile measurements actually indicate deeper bass extension with the 2.2 compared to the 3.7 (!), so your perception seems consistent with actual performance. Note that Tom Thiel still has 2.2s.