96 cadillac STS audio questions

You can add an FM modulated changer that plays mp3s to your setup, but you won't be able to control it through your factory deck or steering wheel controls. 

To do what you want, you could have another deck installed in the glove box, or something.  You could piggyback all the wiring from the factory radio, speakers and all, and install a hidden toggle switch on the accessory lead.  That way, you'd only be able to have one unit on at a time- either the factory deck, or the aftermarket, never both.  If you wanted to, you could use a 70 and 71 series Metra harness to accomplish this, and leave all the factory wiring intact.

Then you could do whatever you like with the second deck, like add a sub/amp, or a changer- which would be controlled by the deck.  If you wanted, you could install a steering wheel interface adapter.  That would allow you to control your aftermarket system through your factory steering wheel controls.  You could play the factory stereo if you didn't want anyone to know what all you had in there, then at the flick of a switch, you could have your sub kick on, and listen to your favorite mp3s.

You're only limited by your imagination (and your installer's imagination is limited by your pocket book ).

i was looking for more of a replacement changer unit in the trunk and would really want to keep using the stock controls on the steering wheel. great ideas!