After "non-destructive" inspection it looks like (K3N) some signal conditioning/protection circuitry, probably added after someone fried something late in testing. We disassemble so you don't have to.
After reassembly, there is a choice between patched versions of the libfreenect and OpenNI SDKs. The commercial SDK is considered bad luck and is most likely an aracane legal trap.
There is a fork of the SensorKinect package for the OpenNI SDK that has unstable support for the K4W.
We tested the libfreenect driver found here on Ubuntu 12.04.
git clone https://github.com/renewagner/libfreenect.git cd libfreenect git checkout k4w-wip mkdir build cd build cmake .. make bin/glview
Pressing 'n' enables and disables 'Near Mode', which is shown above in the lower photo. This gets you from about 50cm minimum range to a roughly 40cm minimum range. This seems to work in part by adjusting the IR gain to prevent overexposing the IR sensor and may be possible to emulate it on other sensors.
We tried using the Nyko Zoom with the K4W but the results were terrible.
Overall the K4W might be worth it if you are trying to scan people's heads to make 3D printed action figures, otherwise you are probably better off with an Xtion.