Amp harnesses

Anyone know if the wiring harnesses are already present on non-Monsoon equipped '07 H3s? I want to add an amp to my nav unit and my choices are a PAC AOEM-GM24 + aftermarket amplifier or, if the harnesses are already there, just add an oem Monsoon amp.
 
Thanks in advance,
Paul
 
P.S. The oem nav unit really does work quite well. I also have a Garmin Nuvii 600 but wouldn't mind leaving it home and using this alone - just need an amp so I can hear the voice prompts (and the OnStar)

Paul,
 
Did you ever get this set up.  How did you complete the install?
 
Thanks
 
Rich

I'm also dying to know.  I have a nav install on mine and the comamnds are very quiet, I'd like to fix this also.