Thiel Owners

Beetle - I suspect the "don't do it" is because the spuriae introduced are evidence of non-linear behavior which can cause problems for some amplifiers.
Rob - the only resistors that benefit from upping are those carrying current, which are in your stock pair. Plus a couple that I can advise on a PM.

Rob - caps always improve via parallel smaller values. Jim never went over 100uF.

Thought I'd pass along my rudimentary update on my exploration journey yesterday.  I managed to  remove the woofer with much labor.  I ended up removing the 6 screws and placing the cabinet, baffle down, on the carpet propped up with  a book on the top side.  Then I ran a 40 hz tone from a generator at about 90 db to vibrate the woofer from the cabinet.  It took about 20 seconds!  Not sure if this is text book operation and hopefully not damaging to the components...  Anyway, I was at least able to verify that the original caps are indeed Clarity Caps SAs as I am almost certain that this is the first re-cap these 3.6s have ever experienced.  As I am a musician by trade and quite the amateur with regard to electronics, I continue to welcome experiences, anecdotes, and any tricks you may have as I continue on my journey.  I am handing with a soldering iron though.  I would image that the bulk of the laborious work removing the remaining drivers and components will need to wait for a few weeks while I finish up my online spring teaching schedule but have plenty of time to dig in later in June.  I did have a chance to look at the Carity Caps website and found the CSAs with ample information.  I also found a next gen CMR:

http://www.claritycap.co.uk/products/cmr.php

Have any of you guys had experience with these?  Also, while I have the crossovers out, what other electronics should I consider replacing that may need replacing? 

I was at least able to verify that the original caps are indeed Clarity Caps SAs as I am almost certain that this is the first re-cap these 3.6s have ever experienced

You must have very late production 3.6s. I would have guessed Thiel stopped making those before Clarity introduced the SA. Interesting. The SA is a good cap but, as Tom Thiel wrote, the CSA is a step up. The CMR is supposed to be even another step up. But those are much larger, possibly requiring a new board to accommodate their size and much more expensive. My new boards have 630V versions of CSA on the coax feeds. It would be interesting to compare 630V CSA to 400V CMR. There is a 630V version of CMR but those are bigger still and more expensive with a smaller range of available capacitance values.

You probably have high quality coils but I would replace any sandcast resistors with Mills MRA-12s.

Jim never went over 100uF.

Pic of @vair68robert coax crossover has a 400 uF EL. I know this crossover was designed after Jim passed. I imagine he will need to use an entirely new board if he chooses to replace that cap (plus a couple of other ELs visible in his pic, presumably >=100 uF). That would be quite the volume in film caps! But possibly worth it . . .