I just replaced the system in my '02. Always thought Bose was horrible because there was virtually no bass. Now with some saying it sounds great, maybe I had an issue with the amp or something. Car had about 40k on it when i got it 18 months ago and I had to put a 10" sub in it right away to stop my ears from bleeding. Now I've replaced the door speakers, 6x9s and head unit with an Alpine 9885 and added a couple of amps. Much clearer now and there's different sounds in the music I never knew existed. Definately worth the upgrade.
At any rate, I wouldnt be too concerned about losing Onstar. 2002 and older, maybe even 2003 cars with the analog system wont work anyway now...or shortly, since Onstar is killing the analog service.
I forget now what all chimes were actually heard before, but the key in the ignition chime is still there after replacing everything. There are no chimes with the car running and the door open which is nice.
The shop I got my radio harness from didnt show one for a car with bose/onstar. They wanted to sell me this $100 thing to keep everything working. I said just give me a harness for a car that doesnt have bose/onstar and I'll see what happens. Worked perfectly.
