Best Stereo Upgrade Value

It always depends on goals. Set percentages can be a guide but those percentages can shift wildly depending on overall budget. I’m presently (waiting for new speakers) listening to speakers that represent 5% of my total system. Many might listen in my room now and wonder why new speakers? LOL, they might be correct.

fully recapped amplifier with the best possible caps which only found in a very best expensive amps,since then I started to examine internals of amps

I'd probably agree with every single post on this thread dependent on exact time and situation of system at that time, this means weak or squeaky link gets the grease.

Distributed bass array.

Speakers first, mono amplifiers second, pre amplifiers third.  All other changes are like adding sprinkles to an ice cream cone, nice but could live without.