Tweak or Replace? The Costs and Benefits of DIY Speaker Mods

My primary speakers are a pair of 1980s-era Belle Klipsch horns in lacquered walnut – which I acquired off Craigslist from the original owner some 30 years ago.  For what I paid, I can only assume someone wanted them gone.  Badly.  They're a bit too large for my listening space, but my modest budget has led me to conclude I wouldn’t likely replace them anytime soon with something markedly better.  They’re also completely stock – save for a pair of Crites AB-2 crossovers and a separate powered sub-woofer.  I currently have them sitting on Townshend seismic bars - and they sound (IMO) pretty good with my 15wpc SET.  Like all speakers, the quality varies by recording and artist; a few of my favorite female vocalists can sound a bit shrill.

With about 5-6 years until retirement, I’m executing a plan to have the best system I can afford when I cease paid employment – selectively purchasing a piece or two each year.  In the past several years, I’ve updated my DAC (Denafrips Pontus II), headphone amp (Quicksilver), and headphones (Sennheiser HD800s).

Speakers are on my list of upgrades, but they’re not a super high priority.  At some point, my plan is to replace them with a pair of Klipsch Forte IVs or Cornwall IVs (probably the former, due to size).  These later versions appear to have quelled or softened some of the previous issues associated with the ubiquitous “horn sound.”

I’ve seen various mods for Klipsch horn speakers – including dampening the horns with Dynamat, upgrading the tweeter, internal wiring, etc.  My questions are thus: (1) Sound-wise, are these mods worth the effort and/or expense - versus, say, just being patient and replacing the speakers entirely? and (2) Do such mods significantly impact the admittedly modest (relatively speaking) resale value?

What I want to avoid is spending time and money in futile pursuit of improving what I have – only to replace the entire kit-and-kaboodle in several years (perhaps at an exaggerated depreciation).  Let me also say:  I’m happy to keep these IF I can get them sounding closer to what the newer versions are now offering.

I’d welcome any thoughts.  While I’m not dead set on the Klipsch Heritage line, I’ve grown accustomed (in a good way) to the sound of high sensitivity speakers played at lower volumes via tube amplification.

Terry