muznut

I am looking at putting an AVIC-Z1 in this truck and have read through a lot of the forums here and have figured out how to make the OnStar work and the steering wheel controls. What I am curious about is, will the factory XM tuner work with the Z1 or do I need to buy another tuner? Also, will I still be able to use the factory rear dvd system with the new head unit? Thanks in advance.