I am in the middle of a custom stereo build for my viking. I made a custom panel in the open compartment in the center of the dash. In the left half of the panel I have six toggle switches that control dome lights, rock lights in fenders, and future additions. In the right half of the panel I installed a JBL prv 175 marine receiver. The unit is waterproof and is Bluetooth. I am Going to build some custom speaker boxes under the roof that are going to house some Polk waterproof speakers. The speakers should come in the mail tomorrow so hopefully I can finish the project.