My experience with Nordost Cables, Blue Heaven and SPM, is that they were lean in the bass and a somewhat bright/harsh in the treble. A good friend got the same results with his Red Dawn.
As far as the bi-wire, myself and a few friends tried this against single wire with jumpers of the same cable on various speakers, and we all liked the single wire better, as it was more coherent. Here is an interesting read about bi-wire,
http://www.sonicdesign.se/biwire.html
If you search the forms, you'll find many different opinions on bi-wire, but I do believe it is best to do a true bi-wire, this is what Vandersteen recommends, which is 2 separate runs of identical cable. You don't need extra terminals on the amp, you just make 2 connections on each positive and negative post. I do encourage you to try before you buy.
Based on my experience and what many others say in the forums, the effects of bi-wire are more obvious in the midrange and treble.