Originally Posted by My Caroline
"Bluestar by Costartech"
These are the ones I know of. They are all shady at best and all require that you have to get rid of onstar. They basically unplug the onstar box and this plugs in to the harness. Are you making a new system that could use the built in mic (the one in the headline/dome light panel) and integrate to the radio WITHOUT getting rid of onstar? Good luck!
Wow just took a look at those and they seam really hoaky