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

I can't say I've made a similar upgrade, but can point out a few things:

1. I listened a lot to the Polks at the time they were out and always felt they were bass-heavy and shelved down in the highs. Keeping in mind I'm going with 20+ year old memory here, the Wilsons and the Krell speakers you mention would have quite a different tonal balance than what you might be used to. You really have to hear them, but then I think you'll see what I mean.

2. The Polk SDA speakers are definitely different than any of the other speakers mentioned in that they had that stereo dimensional array technology which sent out of phase signals from each speaker to eliminate some perceived flaw in typical stereo speakers (damned if I can remember the actual terms they used--maybe the signals eliminated crosstalk or something). The point is that they definitely sound different than most other speakers I listened to at the time; again, you'll have to hear those other speakers to determine whether you like the Polks' presentation better. I recall a lot of Polk SDA owners bought and have held on to these speakers because they are different.

3. Finally, while I think your room is fantastic, the way you have the Polks set up, up against a back wall, will likely not work at least for the Wilson speakers, which do better away from the wall (can't comment on the others, but do note that there are not that many speakers out there today that are intended to be placed close to the back wall).

Hopefully someone who has the SDAs or has sold them can comment more from actual experience; I just chimed in because I did hear them a lot when I first got into this hobby and have strong memories of them.

You should be careful--I had a project with the manufacturer and designer of my speakers where we replaced the crossover built inside my satellite speakers with an outboard crossover using much better quality parts (Hovland caps, Alpha Goertz chokes, WBT binding posts, better quality wiring) with the same values as the replaced parts. The result was not entirely to either my or the designer's liking, as the speaker, while far better in many respects, became almost unbearably bright. It took some redesign work and tweaking to get the sound where we liked it. So I would not discard the old parts until I was happy with the sound of the crossover with the new parts. You can get a different sound, but different isn't always better, at least IMHO.

Mejames--perhaps in another setting, but given their "omnipolar" design, not where Gammajo has them placed in his room.