@indranilsen A superior amplifier / amplifier-speaker pairing, in my experience, will (does) sound "faster" than what one is "used to" versus one’s former pairing... initially.
I have also found that I quickly adjust to the new "speed." The former pairing (once that happens) will sound sloppier and not quite right (in comparison). Put another way, the new pairing will not sound "faster" per se...rather (and importantly) it will sound more correct in terms of musical timing. For example (recording dependant), music can and will sound slower as well. Gaps between notes will be experienced as extended. ETC.
Getting the timing and flow of music correct is, for me, critically important to achieving musical (emotional) engagement and pleasure. This is what better components bring to the table.
I doubt what you experienced was an ’artifact’ related to break in. Again, in my opinion / experience, it is an early and healthy indicator of component performance superiority.
I have heard the M28 monos in person and I walked away very impressed.
It will be interesting to learn which amp you ultimately choose.