I just got my first car about a week ago. I purchased a 2003 Buick Century for about $6,000. I am looking to add audio controls to the steering wheel. I was hoping that someone here would know if Buick adds the same wiring in all of their cars and just doesn't hook it up for the cars without the controls, or if they use a separate set of wires for the cars with the audio controls.

1: Should I even bother trying to add the audio controls?
2: Does anyone know where to get a steering wheel with controls built in?