xm radio wiring harness help

[Carson]

I am installing xm radio in my vette and I'm wondering if anybody has a diragram of the stock gm radio jack harness. I need to locate a constant hot, switched hot and a ground point. Also, does anyone have any suggestions on antenna mounting location, that will not detract from the looks of the car?

Note, I am installing the Pioneer Gex-fm903xm radio

Thanks