BH has this microphone for 179 and 409 w/ with something called K6 (i think). I do I need this "K6", I want to use it as a boom microphone for my XL2.

The K6 module supplies power to the ME66 capsul. It also contains the XLR connector. You do need this to use the microphone.

I would recommend picking up an inline att adapter.. It's a pretty hot mic, so hot in fact (hot as in sensitive and not stolen) I sold mine after 5 days..

I replaced it with a AT825 which gives me a better source for ambient sound fill and really don't need that narrow of a pickup pattern.. At least for what I do..

You need the K6 and an inline attenuator is also a good idea.

Not only is the ME66 hot it also has a lot of off-axis coloration. I have the ME66 and would never use it inside (again) unless in an extremely noisy room where I was trying to isolate voices. I have the ME64 cardoid capsule also and find it a much better all around boom mic. Works fine inside (great for dialog) and ok outside as long as I am not fighting too much ambient noise.

These are good mics, but if I was starting over knowing what I know now, I would try out the ATs before buying them again.