What to do with old Thiel CS-2s

Thiel sent out the CS 2's with the double sided tape on the grills from the factory. These speakers are underappreciated. Though they have are an exceptionally easy amplifier load, the sonic signature requires one tochoose amplification carefully. They have been reputed to be the most durable Thiels ever produced. With that said, they can be found frequently at extremely attractive prices, so the cost for the amount of refurbishing you seem to be implying they need seems imprudent. You might want to considering perusing e-bay or Craigslist for parts or salvage units.

Thanks all. I didn't mention that I did get a quote from Thiel for restoration of the drivers... I was able to buy modern, excellent speakers for less. Their price was ridiculous. And no, they wouldn't sell me the drivers. I do wood working and could restore the cabinets, but not worth it if I can't fix the drivers. I could look for salvage but I also wondered about getting parts from parts express - equal sized drivers - and just installing them. Crossover could be an issue, but maybe there is a kit that might work. Cabinets are heavy and durable. The 2s sounded great but were ridiculously sensitive to different amplifiers. I always wondered why, and the best I could tell it was because the 2s varying in their impedance a lot over the frequency range. They actually sounded best with a b&k st2140. Amps such as a Bryston 3b, a krell ks50s, etc never sounded as good with the thiels. My sense is that most modern speakers are less sensitive in this way... Might be worth calling madisound....

I should also mention that these did not have double sticky stuff on the grills when I bought them, but after the amp blowup, the Thiel restoration included the double sticky tape.. Alas this precluded taking the grilles off, so they weren't checked as they should have been. And then when I did try remove the grilles it ruined the grilles and the surface finish underneath... Thiel might make good speakers but this was an amateur solution.. If they had asked when they did the repair I would have told them not to use the tape - grilles had been fine without it from 1987-1994. Oh well

Trying to replace the drivers with randomly chosen same-sized drivers would produce horrible results. Speakers have many different operating parameters that must all be right to work correctly for a particular design. Your chances of buying even a close match without careful research are zero.

I think your best alternative to original replacements for the cone speakers is re-coning. Hopefully your tweeters are OK. If not, repair may be possible.

I've seen many pairs of CS 2's sans grill, all had the dual sided tape, including the pair I purchased new. Perhaps you had a very early pair? The grills could be removed, unfortunately doing so would remove paint from he baffle. Not really a problem as the grill on this particular model were designed to be part of the smooth detraction efforts, so it would be unwise to play them without the grills, and once the grills were replaced, one wouldn't see the paint damage.
The CS 2's has a very easy impedance load, rated at 6 Ohms nominal/ 5 Ohms minimal. Here's Stereophile's measurements demonstrating just how easy a load it was:
http://www.stereophile.com/content/thiel-cs2-loudspeaker-measurements
I've heard the CS 2's in many different set ups and with quite a few different amps in my own rooms. I ran them with B&K ST 140s for some time. I'm surprised you preferred the B&Ks to the Krell. That was one of my favorite amps with them. I ended up using ss c-j and enjoyed that combo for many years before moving up the Thiel line and changing amps with speakers.
I wouldn't recommend using random off the shelf drivers. I'd suggest find used parts on line or just ditching them and moving on.