Well IDK, maybe the PNW is different. But they are on Ebay all the time. In central Indiana I paid $10 each for two pairs of the 3000's and got the 2000s virtually free as part of a large group buy where the guy just wanted to clear out what he considered to be junk (some of it was) and all I traded was one beat-up guitar distortion box. So my 3 pairs of Allegros cost me roughly $21. Ebay sellers typically ask too-high prices, and TBH, I would never pay $90 for a pair no matter how nice their condition.
If there is a problem with the woofer then IMO it is no-brainer...get your money back while you can. For your good money you shouldn't live the the problem as it exists and, more importantly, it could get worse. Thus far it has been a pleasant experience in listening and learning. There will be more and (some will be) better opportunities further down the road. In an 8x8 room, any 10" woofer, or most any 8" likely, will give you as much bass as you want.
As for removing the backs, which I did suggest before, having seen that pic above the back appears to be very tightly fit against the sides. Even if you get the screws out, my guess is that some damage would occur to the particle board when removing the back, either to that back itself or the ends of the sides. So no, I do not think you should remove the back now. Damage it and you lose the ability to return it.
