Car audio questions.

Hi everybody. I got a 1997 Lincoln Town Car Signature Series in damn near factory fresh quality. The only problem I have with it is the stereo system sounds good, but it isn't the greatest. I am planing on changing out the speakers, but i would also like to change the head unit. is there any aftermarket stereo i can buy that will let me utilize the steering wheel radio controls and the 10 disc changer?