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


I am considering upgrading my 25 year old Polk 2.3 SDA speakers to something such as Wilson Sophia, Krell Resolution 2 or Usher Dancers. I have already upgraded the tweeters in the Polks and was very pleased with the difference. Over the years I have upgraded amp to Aragon 8008BB and source to NorthStar trans and DAC and also noticed improvement.
I live in a rural area and am willing to travel 8 hours round trip to hear new speakers but very little chance I can hear them at home before purchase.
Please, oh wise one's anyone make a similar upgrade and were happy or not with thier purchase? If happy, what type of improvement might I expect? Thanks
gammajo
Thanks Aktchi, sage advice. I talked to Polk Audio today. They were very helpful. What he said was that if I was 95% satisfied with my Polks, then doing crossovers and new cables etc might bring me close to 100%, but if I was 70% satisfied, then another speaker might be a better place to put money. I'm probably 90% satisfied with the sound but do not like thier size and dated "big door" shape in my room.
So today been exploring Van Sneikert(sp)VR4SR and Gen III options etc. I will let you know how the search progresses.
the Vons are a great speaker but I know that they need more room from the back wall then you will be able to give them so I would shy away from them.
Aquick note that my father has the Legacy Focus 20/20 and his speakers are only maybe a foot from the back wall and they really sound great, they are also a beautiful speaker with top notch cabinet work.
I would try to stay with a sealed enclosure if you look into new speakers for clsoe to back wall placement, or atleast not look into any that port towards the back wall
a minty used set of hales(heavy, but not as big as the polks) and a fraction of the cost of speakers that are nowhere close to being its equal.
Chadnliz - thanks for your comment. I looked at Legacy - gorgeous but at 55" too tall for me in front of window placement. I am looking for 45 inches or under. Talked to VAN's son. He states that he has his Van jrs at 12" from back wall and they do fine. And that the newer Vans are designed with close to front wall pacemnet in mind. Do you have experience that contradicts this?
Jaybo. Thanks - I will look at the Hales.
All speakers radiate bass in all directions..so you will get some reflections and cancellations from the rear wall....the only way to eliminate this is with acoustic treatments,with soffit mounting or placement very far from the wall. (as someone mentioned, ports can often make it worse and I agree, as tuned ports have a strong resonance/nonlinear response)....see this link for details

http://www.genelec.com/support/flushmount.php

I am surprised Van jr did not mention this...as it is well known.