08 GMC Sierra-Upgrade Xm to NAV XM.?

[WantABully]

I have an 08 GMC Sierra with the stock in-dash XM-FM-CD with the factory XM roof antenna. If I wanted to upgrade to, lets say a Pioneer in-dash XM-FM-CD-DVD-NAV system, would the stock antenna connect, or would they have to install an aftermarket antenna?