Very doubtful, but the voice prompts should remain:
Retains OnStar® system functionality when the factory radio is replaced in an 11-bit GMLAN vehicle. Generates all safety warning chimes and audible turn signal indicators.
Yep that's exactly what you need. I have my metra harness combined with an ASWC module so I have factory steering wheel controls on my Pioneer navi.
I use the GMOS-LAN-04 - it costs around 100$ on amazon/sonicelectronix.
The ASWC is around 45 on amazon for steering wheel controls and the antenna adapter - the 40-CR10 from metra or CRAB from scosche is around $5
combine all that and the dash kit for a double din : the 95-3302 from metra and you're all set.
Let me know if you need any help.. Great choice with the pioneer by the way
EDIT: programming the steering wheel controls was not fun on these cars because you have to hold the volume up button, which kicks on onstar and turns off the radio, so I ran a constant 12v to the ASWc and radios 12v switch until i programmed it and then rmeoved the 12v constant after
you need a interface, gmos-lan-03.
it'll take around $100. I have a spare one. Just used for a few days because i don't like the after market radio, then switch back to oem radio.
I can sell it to you for 60$ if you want. t.ge@me.com