By a strange coincidence, I am sitting next to our radio in our Sovereign
. It's pretty straightforward, you will need to unscrew the two screws holding the handle in the front housing, and remove the handle. After that, there are several screws and clips holding the front mounting plate in place, and the knob attachment nuts on the front of the radio. There will also be a fader control in the front mount plate, you will need to remove the mounting nuts for it as well. I cut the wires leading to the fader control, as our new radio has one built in.
Each speaker has two wires that go to the radio, if your new unit has a common ground, you will need to ground the speakers.
Let me know if you need more info, I'll try to get more in-depth.