25 year old polk 2.3's will I hear an improvement?

There is no correct or incorrect answer to your question. Here is my story. I owned the Polk SDA 2.3 speakers for a number of years myself. The upgrade bug finally caught up with me and I replaced the 2.3’s in 1999. I also was not able to audition or hear the speakers I purchased in my dedicated room. Bottom line is that although the new speakers were an improvement, I was amazed as to how good the 2.3’s actually sounded. The cost of diminishing returns enters into the formula. If you have the big bucks to spend for new speakers (I would guess at least $5000 new / less used) and you realize that there will be improvement, however most likely not to the extent you are imagining, go for it. Over all I was happy with the new speakers however the SDA 2.3 speakers do a lot correctly. Good luck!

Lak, Thanks. A wise way to look at things. May I ask what speaker was an improvemnet for you, so I can get an idea of type of speakers that helped and what improved? The tweeter replace took care of alot of the problems in the highs, adding sweetness and detail.

Since you've already upgraded the tweeters, you might want to try upgrading the crossovers with high quality parts. You may find that to be all you need.

Merganser - you may be right. So far I have been chicken to do so, since I do not have the personal expertise, but I will probably go listen to at least a few systems that proclaim to be great in good settings and if they blow me away look for new speakers, if they dont then I will consider crossover upgrade. But I have heard that sometimes the upgrades dont work and they ruin the speakers - any truth to that?

a lot of sophia owners would crap if they heard how good your sda's sounded.