Quick few questions for sonic007, or anyone else who knows - let's assume we're installing an aftermarket HU with nav, Bluetooth handsfree, XM, aux input, and USB, using the Metra kit, into an LTZ with all the bells and whistles.
Is it possible to interface any/all of the following factory equipment with the new headunit, to avoid having to install new redundant stuff?
XM and GPS antennas
handsfree mic (and steering wheel dial/hangup buttons)
glove box USB port and aux input
Let's also assume we aren't concerned with keeping any of the Onstar functionality, since some of those things probably interface with it as well as the factory radio.