IMHO, I would have to disagree. I have had my KSP 400s bi-amped and not bi-amped... and there is a DISTINCT difference in how much the midrange opens up and how little sibilence, if any is experienced when I crank it loud. As a matter of fact, I am so impressed with the difference in bi-amping, that I am considering tri-amping with a tube amp for the high frequency driver. Currently using 3 HK Signature 2.1 amps (100 watts x 5, 100 amperes, all channels driven 20Hz - 20kHz) in my set up with KSP S6s for side and rear and KSP C6 for center. Also, KSB 3.1s, 2.1s and SS-3 for presence channels and KSW-150 for rear sub. My complaint is that the S6s and C6 are not bi-ampable. Imagine how much better the S6s could sound with bi-amplification!
I couldn't say the same for bi-wiring, though... unless the cables were specifically wired to separate the high frequencies from the low frequencies. There are two schools of though on this: those who are for it, and those who are not - just like bi-amping. [*-)]