replacement radio for 1982 300sd turbo

Any advice or suggestions for replacing the original am/fm cassette. I'd like to keep the existing radio and add an in trunk cd changer. since the antenna lead is in the trunk a cd changer that uses the antenna input seems a logical choice. Also all but one of the speakers is dead. I need a good replacement speaker. Keep in mind that this is a diesel and does not have ideal accoustics.