The LazyAssGeek’s

The Peripheral line of integration modules seem to be the most consistent for C6.  These apply for all C6′s (including Z06) through 2008.

• If you do not have Onstar then the module to use is the GMCO. 
• If you do have Onstar and Bose then you would use the GMAH24B along with the GMAHCM(Application guide says you do not, but you do in fact need the chime module!). 
• If you have Onstar and non-Bose then you use then GMAH24A along with the GMAHCM.

Here is a link to the Peripheral application guide.  They list it as 2005 Corvette, but it’s the same for all C6 model years.

http://peripheralelectronics.com/techPDFs/1Head_Unit_Replacement/GM_00-07_Add-A-Head.pdf