Anyone ever experiment w/ better circuit breakers?

Glen's statement is correct that the brand of the breaker panel normally dictates the brand of breaker. Bolt-in would provide a more solid connection, but there's another alternative.
Take a giant step backwards in time & install a small fused disconnect branch circuit panel, paralleled off your mains, before power even reaches the main disconnect breaker. Source your dedicated line(s) from fuses, which sound better than any circuit breaker. Old ceramic fuses sound best but the new plastic ones are OK too. Just don't use glass fuses, they're not nearly as smooth sounding.

Bob is right as far as my ears are concerned. I threw all circuit breakers out and installed ceramic fuses. Much better punch and dynamics. Cheers,

Would someone like to set some percentages on this tweak? After (a) dedicated circuits, (b) hospital grade wall outlets and high quality in-wall cable, (c) a/c line filters, and (d) audiophile grade power cords everywhere (not to mention the Quietline shunt filters in every unused outlet), am I REALLY going to be able to hear what changing the circuit breakers does??

Flex, you pose a tough question. When I was persuaded by my technician to change to ceramic fuses on all my lines, I pretty much had all the tweaks you mention already installed. I did the change more for puristic reasons, but being basically doubtful. But having done so, I had the distinct impression that the music came through with better dynamics. I cannot give you a percentage, it happened a few years back and the ear adapts so quickly to positive changes, which hence seem normal immediatedly. Of course I cannot be sure, if this is once more a case of autosuggestion, but then, if I had to start from scratch, I'd do it again. Cheers,

Whatever you do, do not use ground fault breakers which are extremely noisy.