But I wanna maintain the factory look, and I want the RDS.
Plus... I wanna make sure that my onstar, chimes, and steering wheel operational switches still work...
They do have some inserts that will make it "almost" look factory, if you get something else.
They also have wiring to allow the chimes to work through the speakers (don't ask me where I saw it, but this place online had a lot of adapters for iPods, and other stuff, that you could "splice in").
Regarding the BOSE, I like the way it sounds... I'm sold on it vs stock. The thing about BOSE is they strive for "natural" sound. No artificial base boost or whatever... The low tones are low and powerful enough to feel them, but not loud enough to be heard outside of the car, or to loosen panels and create annoying sounds.
Bose actually designs the sound to the car (the enclosure), and that's why you can't purchase a Bose car radio... they just don't make it.
If you purchase the stuff, you will have to get someone to reprogram it, because of theftlock. The VIN must match. You will need new wiring, and I'm afraid only GM and perhaps the service manual [to a limited extent] can help there.
Edit: the number of speakers will be different (as will the type of speaker) and I believe each speaker comes with its own amp--it won't be an easy project, unfortunately.
Edit: the wiring to keep the chimes and Onstar, is for "GM cars" so that should help you find it, hopefully.