Let me say this: I know the components I'm running right now might not be drop-dead neutral. But, Man, that slightly modified Audio Research Reference 6 feeding the D'Agostino Master Audio Systems Momentum S-250 is So Musical. Wow! Even Dan D'Agostino admits that his latest creations don't measure as well in the lab as some of his old Krell stuff. He went for musicality over measurements.
Tweaks, on the other hand, are, well, tweaky. Inconsistent. I probably would be looking for another preamp right now had the Synergistic fuse and the Sain power cord not been so effective. But I did try aftermarket fuses in Ayre amps, when I had them, with little change in sound. I tried a Sain power cord on the D'Agostino. Nope. A little to lean. I went back to the stock cord. So, my experience with tweaks is that what might work well in one component or system might not be beneficial in another.