Replacing Head unit in '06 AV

Morning folks!
I have an '06 AV with the Bose sound system, OnStar and steering wheel controls. Mine is a late '06 and also has a microphone near the cluster by the right side of the drivers side sun visor. I also have the steering wheel controls. I would like to update the Head unit so that I can connect via bluetooth or USB but I want to keep all the features I have. I would not mind if the HVAC controls were part of the head unit. Am I dreaming? I have done a couple searches here and seen bits and pieces but nothing with an '06 that someone has actual said worked with existing controls and OnStar or that mentioned HVAC.

Thanks!

Forgot to mention that I have XM Radio and want to keep that too....

Thanks!

You might want to look at www.crutchfield.com website and contact their customer service, they are great at helping you design a system for your AV and it can include all wiring harnesses and adapters to keep all your functions. (I don't know about HVAC tie in though?)

Let us know what they say and the price range