My 2007 H2 needs some help in this department...everything works as it should, but I would like to install a touch screen with nav and bluetooth functions.
Can you re-use the GM Nav antenna with aftermarket head units?

I know I will need the adapter for onstar connection, and my stock back up camera wont work with Sony unit.
The rest of the install I have done many times. (Also installing Kenwood 2 ch and DB Drive subs...nothing crazy I usually jam metal and country)

Never dealt with aftermarket nav systems, or whether or not its worth the cost to not have my Garmin hanging from the windshield?

I love the 10 inch infotainment system in my wife's Charger, the GM factory system is lacking and restrictive when you compare them.