Sorry, wasn't allowed to acces the site, even when cropped down to the base url.

About the Mute wire - yes, for instance if you have a handsfree kit for your cell phone with such an output. I believe someone has wired it to a radar detector...

Also, be sure to check out the car installation issues part of the FAQ. Maybe especially the ISO Wiring connector confusion part of What are the most common installation issues question.

/Michael