Can I replace the stock stereo in my 2007 G6 without keeping the DIC?

GM designed their radios so you can't remove them from the car. There's too much money to be made by their two grossly over-priced repair centers. What you can do is add a "relocation kit" that lets you cut the speaker wires and run them to your new radio, and mount the old radio in the trunk. The Body Computer is in the old radio and is needed for chimes and many other functions.