Just get ur self a aftermarket install kit there cheap and can be attached to any cd player...And if your not planning on running any subs then the factory cd player is ok..If you r running subs defintley not a factory player...:stickpoke
Yeah, just get a FM modulated 10 disc CD changer. That way you have cassette and CD. That's if your head unit is loud and good enough already, just keep it and add the changer. They're really inexpensive. Local stereo shops have last years Sony, Pioneer, and Kenwood changers for $87- $150 installed.