2002 Tahoe CD MP3 Installation

Hey everyone! I have read through some of these forums and found them rather useful.  I am trying to install a JVC KD-SH9750 ( click to view) in my 2002 Tahoe. I'm having trouble with any sound output and have a feeling it has to do with some factory amp (I've read about this but not sure where it's at) or the OnStar that I have.  I went to Metra's website and found that they have a "GENERAL MOTORS TRUCK "ON STAR" PRE-AMP HARNESS/199".  I'm not sure if this is what I need to maintain the functionality of the OnStar or if it will also get my new CD player to work or what.  The link to the wiring harness that I was looking at is HERE. But, before I knew this was going to be this hard I had bought a American International GWH-344 ( click to view) wiring harness to install my deck. It powered own and some times sound could be heard but when I shut the ignition off and back on I could not hear anything.  There is a second wiring plug that is smaller and I think it's for the tape deck or the audio controls for the second row in the center console.  I have a couple questions around this installation:

• Can someone help me out with the installation of this new CD player?
• If I swap the factory deck does anyone know if the tape deck or the audio controlls in the center console will still function?
• Does anyone have an electronic source or copy of the 2002 Tahoe Audio Wiring Diagram?
• What is the smaller factory plug used for that plugs into the factory deck?
• What is the wiring harness that I listed above from Metra's website used for? The description is vague and there is no picture to view.

Any help is much appreciated.

Thanks

Than you both for the reply.  Metra Tech - You stated that I "should not try looking for it on your site".   Where could I find this item since you have it.  I do not have the Bose Setup either.  I would be interested in finding out the price of this part and how I can purchase it.

Thanks again