recommend speaker for Krell KRC and KSA-200S

Interesting question, and I will try to be brief.

First of all, I would contact Krell to see if they will still upgrade the KRC to the KRC-HR. There is a significant difference!

Then, I would be patient and try to find a pair of used B&W800's (matrix). I think that they will fit in your budget. [The unfortunate thing is that, like the KRC, the 800's can also be greatly improved by upgrading (actively biamping with the Krell KBX, but Krell no longer makes them or the board for you speaker.)]

Disclaimer:
I own the 800's. First in the original form driven by the KSA300S and then the FPB300 (a noticeable improvement). I now have them actively biamped with the KSA for the bass and the FPB for the mid/highs.

Have fun!
Richard

Krell no longer does the upgrade to HR.

How about B&W802 or 803D as they are more available in used? I tried out the Paradigm Studio v100 but they were too bright and hash..

After owning several pieces of classic Krell equipment from the KRC and KSA era (pre digital camera days but my early feedback shows the gear sold) I can honestly say that I enjoyed a pair of Thiel CS 3.6's for many, many years. At one point, in a basement that was slightly larger the the room you describe which really gave me the best sound from them. Once Thiel CS 3.6 speakers are fed good clean power with current they will play anything well and are quite capable of tremendous bass output, clarity, coherence, imaging and "scared me to death" dynamics.

Thiel CS3.6 speakers can be found here for much less than your budget and leave lots of cash for quality cables(very important match for Thiels), room treatments and the best part........more music purchases.