Hello everyone and thanks in advance for all the help you can provide...

So, i have a 2005 Impala 9C1 (police package, base model) with a stock radio/casette head unit. I was thinking on upgrade it but i've recently found on amazon, this little device wich is an aux imput adapter for this type or stereos.

I specifically found this:
Pac-Audio.com Product Details | iPod Integration for your car and More by Pac-Audio - Connecting you to the future

So reading about them i've found out that, apparently, head unit needs to be XM ready or have a CD changer in order for this adapter to work. But i'm not fully sure since I've also found this post on another forum that said that someone has already installed one on a 2005 impala (diferent adapter model, but same basic adapter type), and only by presing the TAPE/AUX button (wich my stereo does have, but currently does nothing when I press it) will work.

How do you put an aux (mp3) port on stock radio - Chevrolet Impala SS Forum : Chevy Impala SS Forums

In the back of my head unit, on the stereo himself I can see two connector imputs (12 and 24 pins) but only one harness connects to it (24 pins). In the adapter kit I can see in the included harness that it actually have both (12 and 24 pins) connectors.

So, would my head unit automatically recognize the imput from the adapter as soon as I connect it and activate it when pressing the TAPE/AUX button?!
What do you guys think?! Has anyone heard of them before?! Has anyone already installed one of this?!