[cdru]

I beleive the common thing to do is to relocate the factory deck to another location while still leaving it hooked up. This allows the chimes (and OnStar if you had it) to still operate. There are also some BCM programming options that require the radio to program and relocating the radio allows them to still be modified. I would contact Crutchfield and see if they can give you some help/ideas as to exactly what you might need.

Don't forget that if you have rear audio and want to keep that, you will also need to keep your original radio.