Greetings!

You might want to look at my install. I used to have a Bonneville, but I have a Riviera now. Very similar Buick setup, though. I do not use the steering wheel controls for the empeg - I have the factory stereo going through speaker -> line adapters into the aux in of the empeg. This way, I have the steering wheel controls for the radio/CD/tape, but still have full empeg functionality. Not that I have ever used the factory system since putting the empeg in...