Is Bi - amping worth the trouble?

"Headroom" usually relates to the extra energy the amp has available to deal with (loud) transients in music without clipping.
Back to biamping --
a) I wouldn't have much to add to Sean's post above.
b) A quick reference of what you may expect with "passive" biamping is given by warjarret above. The result doesn't justify the cost -- esp. when compared to normal biamping (i.e. amp directly driving the drive units). That's a different level altogether.
...Unless you have a notoriously underpowered amp -- which you don't.

If V Scheik really means what he says about these spkrs having been designed for bi-amping, then he can provide you with the cross-over schematic, and you can take it from there.

Gregm
Many thanks. ...well that's what he said to me on the phone, when we first spoke of the JRs set up. In fact he said the best two amp set up he had heard on them was with a vk60 & a vk solid state driving the lower unit. he did seem sincere enough that I believed him.

Having heard several medium eff speakers, (84 - 88db), I've haerd them with 200wpc - 600wpc... different spkrs, & different amps... the bigger the amps current supply, the better the sound. Everytime. IN both dynamics, and control. the quality however did not necessaryily improve. hence the desire to add a tube amp in conjunction with mine.

With 84 - 88 dB speakers, you could never have enough power. This is why you've heard very noticeable improvements when providing them with drastically increased amounts of reserve.

Other than that, i would consider 84 - 88 dB speakers to be low efficiency, not medium. Of course, i'm talking about using 1 watt @ 1 meter and not 2.83 volts @ 1 meter standard of measurement. There can be HUGE variances in rated output using the latter format depending on the nominal impedances of the speakers being compared. Using 1 watt provides a FAR more uniform standard of measurement. Sean
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Blindjim,
You're welcome. I'm happy to hear that you find me helpful.
Passive bi-amplification amounts to sending the signal from two amplifiers into the speaker's passive crossover and, unless lack of power is an issue, does not differ substantially from bi-wiring.
True bi-amplification places an active crossover between the preamp and the power amps, sending the portion of the signal that you assign to each amplifier and subsequently to each driver (or driver set). An active crossover will normally afford much more flexibility by allowing you to alter and adjust X/O points (frequency cutoff), crossover slopes (db/octave) and increasing or decreasing relative gain.
It also does not usurp a large portion of your amplifier power as the passive crossover in your speaker will.
I am not very familiar with VS design but I'm sure I've owned something like them in the past. Unless they provide you with a way to completely bypass their internal crossover, they are not setup for true bi-amplification and the advantages it affords. Please remember that much of the advice you receive from dealers, the factory and even certain, if not all, reviewers is driven by marketing interest. This forum is a good, neutral source of info but you need to be aware that at least some of what you read here is the well-intentioned echo of the aforementioned marketing people.

As a cost saving measure, remember that when you bi-amp, you need amplifiers of far less power to achieve the same loudness and headroom. With Magneplanars, I was unhappy with a 35 wpc tube stereo amp, but fine with two of these, passively bi-amped (AKA dual-amp bi-wired). So, I could concentrate on fine quality amps, but not necessarily high-power fine quality amps.