Jon on Alki

Hello, I have this pair of speakers I would like to know a little more about, and if I can make any improvements (not that they really need it ). Here is a description of what I have and all the numbers I am able to find on them. There are no stickers or labels other than the Klipsch badge on the grill. The cabinets: Square (not angeled) Square grill attached with velceo tabs 21" high 15 1/2" wide 13" deep Squawker: K-55-V Woofer: K-22-EF 12 inch (67-7943)? Tweeter: Motorola "something or another" Stamped in the rear top edge of the cabinet is: 92 U 880 I bought them about 18 years ago for $100/pair and they looked old then, but I have not heard any better sounding speakers within a moderate price range. I LOVE them! A "neophyte stereo techie" friend of mine convinced me to have them "ported and tuned"? He had a friend of his insert a 4" X 10" piece of PVC 2/3 of the way into the lower back side of the cabinet and seal it up. I did not notice much of a difference except when I put a lot of power to the speakers the low end sound stays intact. In fact, I have never heard them start to "come apart" I appreciate any info I can get on these. What are my chances of finding another pair and what would I have to pay for them? I'm currently using them for a two channel home theater and general music, but I would like to go with a full surround sound system. Are these speakers going to work for that purpose? They are hooked to a Sony STR-DE925 and they sound beautiful. Again, thank you in advance for any help.