I havent purchased the Aux-Niss unit yet. I am still looking for alternatives to the $99 price tag just for a black box with soldered connections. If you goto
informative Thread regarding hacking the Aux-input
I have been documenting the progress and frustrations..
I just read on the Maxima board that I posted above that people were getting noise with the Aux-Niss box that was due to poor grounding.. So its more reason for me to look for an alternative.
Good luck if you buy it... The instructions should be straight forward. Just plug it into the CD changer port on the back of ther radio, and use the splice connectors provided to tap into a 12 volt positive and a switched 12 volt positive.