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

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.

Gammajo,
I replaced the 2.3's with a pair of Legacy Signature III speakers that I purchased new from Legacy. I noticed different mids and highs. They also seemed to be more open and lifted the veil. I'm about to put them up for sale as I now own a pair of Montana EPX speakers.

Thanks Lak. Loved your naughty comment, Jaybo. RCPrince thanls for the tip re crossovers.

I am being seduced! Since I haven't heard any of the products except my own, I have been going on the glowing reports of stupendous sound in the reviews and adds. Just for fun I pulled the original Polk reviews from decades ago - same language "Audio Video Grand Prix Winner", "Mind boggling powers of sonic persuasion, spectacular, astounding, no compromise" - High Fidelity Mag, etc. even the photos of the big black speakers look cool under soft red light from the side.
I told me wife - "These mags create lust". She looked up knowingly from her New Homes magazine - I am in trouble.
I guess we all like to be seduced, at least until morning.

Gammajo,
There are time tested crossover upgrades for your speakers that will put even more emphasis into Jaybo's statement. Email sent.