Door dings don't go to the car stereo.. You ever notice that your stereo isn't on when you open the door?
Nothing but antenna, ground, dimming, trigger, and then the speakers.
You may need an aftermarket adapter though if the harness uses proprietary connectors, which I don't think the Malibu does unless it's 04+. I can't really tell you that. Companies like scosche makes them. But since I can't find one anywhere I doubt you need one.
So I say just wire it up and you should be good to go.