Unlike the slide implies, the Kurzweil system does not have more headroom than your DAW. In fact, you would be doing a highly destructive DA/AD/DA conversion in this process, during which the noise and quantization in and out would further degrade your audio. So unless you had a severely limited DAW (in which case you would not be able to feed multiple out lines to your Kurzweil anyway) this would reduce, not increase, your quality.
They have a digital interface for the Kurzweils, although it\'s not cheap. Even with it, though, I personally would rather use their stand-alone fx unit than try to route signals through one of those instruments in any hurry. The KDFX sounds nice, but even though they did a good job of integrating it with the instrument, it is an added-on layer. It\'s not quite the same thing as routing signals through a mixer. You forget what to push very quickly!
And this is coming from a longtime Kurzweil user who owns several of their instruments.
(I\'m assuming it\'s still the same in the new Kxxx instrument - what I\'m saying is about the K2500 and to a lesser but still relevant degree the K2600.)