Speaker Cable Upgrade Path Advise, Please

I have a McCormack DNA-225 (Ensemble Megaflux power - BD racing cones), Kora Eclipse preamp (Harmonic Tech Proac 11 power - Ensemble points), PSB Stratus Goldi speakers. Using both digital (classe CD) and analog (Nottingham TT)sources. Harmonic Tech TruthLink interconnects.

Initially I was using 8ga. Monster speaker wires until I was given an 8' biwire set of Cardas Crosslink cables as an "upgrade". Frankly, the wires sounded better. To say the Crosslinks (120 hours on them) are BRIGHT, is a gross understatement. I have been waiting to buy speaker cables that complemented what I like - crisp highs, to be sure, but also "mellow" midrange and thumping, tight bass. Any suggestions as to 8-10' biwire speaker cables in the $500 USED price range for my situation and setup?
My favorite is the Blue Circle BC92. An 8 foot biwire pair lists brand new for just under $500.
I probably should qualify my comments about the Crosslinks a bit. Yes, they are the bottom of the ladder in Cardas. But, they do provide surprisingly excellent soundstage and good imaging. The midrange is good, but the highs are stratospherically high and the bass veiled and muddy - at least in my system.
I have some Kimber 8TCs and they sound very good compared to the cheap cables I have used in the past ! And also a set of Kimber KCAG for your cd player and amp to preamp connections should get you back seriously into the NEUTRAL ZONE!!!!!!
I would suggest you consider the Harmonic Tech Pro-9 bi-wire cables. I have not personally heard them, but I am familiar with the truthlinks you own. I believe that if you pair them with the Pro-9s you will achieve the sound you described. Also, through experience I have found that it is beneficial to use one brand of cable throughout a system. That's not to say that you can't achieve great results by mixing and matching cables, but if you like the truthlinks and the Pro AC-11 I don't think you will be disappointed with the Pro-9s. There are some used pairs for sale here at audiogon in your price range. Check out the latest issue of UHF magazine for a good review of the Pro-9 bi-wire.
I used to use the Crosslinks, and although there are certainly better cables above these to be had for not too much more money, I wouldn't have described them as "bright". In fact, I chose them at the time because they were smoother than the entry-level Monster and AQ stuff. I've since upgraded to Cross, which actually lets more of the extreme highs through, but does lose the congested lower treble, removing what I would describe as a "hard" sound in the Crosslink. I agree about the somewhat muddy bass, but maybe the "brightness" you hear is actually present somewhere else in the system, and the Monster wire was merely suppressing it? But basically, I would say that Crosslink is just not enough wire in between the DNA 225 and the Sratus Gold's; try a good cable with a guage closer to the 8ga. you were running before. And oh, don't overlook the possibility that bi-wiring may not agree with your setup - this could have been a confounding variable. Good luck!
I have just found the speaker cables you are looking for,
as I was looking for the same thing.
Pair of "Virtual Dynamics Reference" bi-wire cables,
I have been on a cable hunt for a while and these have
it all.
These were a pair of 10' Cryo treated cables, $2k new, found
on A-Gon for $675 used. If you can find a pair get them
you will love them.
Most of your gear leans toward the forward (bright) side. I'd recommend biwiring with double runs of Tara Labs RSC Prime 500. This cable will provide slightly toned down high frequencies without sacrificing the detail and resolution you want. They should also enhance and define the bass response. Even with two runs of this cable per speaker, you would stay within your $500 budget buying them new. Tara provides excellent factory terminations of your choice. I'm using this set-up between my McIntosh MA6500 integrated amp and my JM Labs Electra 915's (also considered on the forward side) and the sound is intoxicating.