May all your problems be solved for those of you who want to install an aftermarket radio into a 2000 or newer Bonneville. Metra has a subcompany they call Axxess. There are two types of Axxess digital interfaces. If you have OnStar, you'll need the GMOS-05. If you do not have OnStar, you'll need the GMRC-04. The only website that I found that sells these two adapters was given to me by the folks at Metra. The site is Lafayette Radio: http://www.lafayetteradio.com/. The people at Lafayette Radio are real friendly and very helpful. Each adapter has a speaker built into it for retaining your warning tones and door chimes. You can completely remove your factory radio without compromising the computer system. If anyone knows how to make this topic sticky, let me know. I want everyone to know this because it took me forever to find this information out.