I found this part on www.gmpartsdirect.com (http://www.gmpartsdirect.com) part# 12498768.
Has anyone done this and whats involved.

That looks like the stock factory XM kit, same as what Merchant sells.

If so, you install the XM box behind the glovebox, install the antenna and run the wires to the radio. Then you call XM and start your subscription.

Or, you can get the GM XM Direct kit from Terk, for half that price.
I went with the SIR-GM1 kit. Both will play through a stock sat-ready head unit.

How do i know if my radio is sattelite ready.I have the single disc cd am-fm in a 2004. Will i have to add another antenna? Please send me the links to the other vendors also.

The only radio that isn't XM ready is the basic WT one. Your single CD unit is fine.

For Merchant's link....see my sig.

Thanks cant find the link though?

Sorry...I guess thats no longer a link....my bad. sent you a PM.

The GM Xm unit is the only way to go if you have the Nav system. The other units have a few quirks with the nav system. They should work fine with the other stereos however. The GM one definately works the best. IF the price doesn't scare you and you want XM over Sirius then definately go that way.

I chose Sirius because of NASCAR in Jan 07 and NFL.