Underspent on speakers relative to overall system?

Still, eventually there comes a time when if you want a jump in performance you have no choice but to replace your treasured speakers, and often even used this will cost. 

There is a simple and preferred method - to try tubes.

The speakers that I have are Michael Green Audio free resonance speakers. They sound different with their advantages and disadvantages, they also require very tight control by an amp. Replacement will not be easy.

I bought my current speakers used 18 years ago for $500. Then I bought used speaker cables for them for $550. And as it stands now cost of speakers is around 6%-7%. Not that I cannot afford better speakers, I cannot afford much better speakers, and until I can things are going to be as they are. Just got power cord for the integrated amp that cost more new than the amp, both were bought used of course for $650 and $750 respectively. Nice impovement compared to $800 new cord that I had before. Purist Dominus Ferox replaced Custom Power Cord Company Top Gun. Despite looking wild on paper, the entire system is quite balanced, needs one better interconnect and one more better power cord. After that - nothing until I am ready for new speakers. And then it's all over again, but I am sure the Dominus and Neptune interconnects will stay, as will Nottingham Spacedeck. Arm, cartridge and phono stage will most likely be replaced along with the amp and speaker cables.

I think, you underspent on cables, 27% speakers sounds fine.