I have a set of Bettercables Bluetruth biwires enroute for my center channel but I plan on trying them on the Polk 15s to see how I like them . I am running Cobalt Cables now so I really will probably only see the difference between the two cables if anything.

there will ALWAYS be a debate an passive bi-amping,but in my case it cost me 0$ to do it to my 601's(b&w not bose),and i like to tweak,sometimes bass and treble just can't do it.a little tweak to the gains on the back of my b&k can be just what i need!if it's any indication of the performance i do really like it,but,i have an urge to buy a pair of 602s(604s are not gonna work in the basement and $$$) and i will break them in with my straightwire encore cables and really doubt i'll go back to the biamp gig.

as far as my opinion on biwire: useless,unless you want to 'up' the gauge of the wire(using 14/4 instead of paying for say 10 or 12 gauge)

which is exactly what i'll do when my 601s move to the rear.

and 'hound,i can tweak my gains on the b&k blind,does that count