Replacing tape cassette head unit
 

I'm going to be replacing the head unit in my 02 Monte LS that has a factory cassette head unit. Does mine have a factory amp in it? I looked in the rear deck and didn't see one, as I believe that is where it is supposed to be located. As I had read of some having problems with an aftermarket headunit with the factory amp.

And mine doesn't have Onstar. But I had read of some using the GMOS-04 adapter that is supposed to retain the chimes through the speakers? Is that correct? I'd like that better than having a little chime box in the dash. Though I had read of some having noise problems with the GMOS-04 adapter. I think it had something to do with the RCA cables.