Couldn't find so here is a summary.
I installed the UD650 Fusion B/W head unit, 4" Fusion Speakers in the cabin bow area (direct replacement for the Kenwood 4" even used the black water deflectors that were installed by the factiry and 6" speakers in the helm, even used the wires), and 6" Fusion Speakers in the helm in my 06 Marlin. I used a wire snake under the cabin headliner and ran the cable for the Fusion Remote under the headliner to the stock mounting point on the port side cabinet above the microwave. The snaking took some time and I had to go to the middle of the headliner. Take your time (maybe us the existing Kenwood wire and pull the snake thru from the stereo). I ended up needing to snake it but it worked out very well. I had to enlarge the hole in the dash for the remote. I don't use the Sirius thus don't need the antenna, just left original in place. If you want XM, you need a new antenna (existing antenna connector is unique to Kenwood) from Fusion that plugs to their head unit. Not expensive to buy.
I mounted the Fusion 2 channel amp and wire kit in the aft cabin port side bulkhead. I removed the large port side panel for access (directly under the Fusion head unit). Used 3M double sided stick tape on the amp and placed on top of the AC plastic tank then wrapped in two places with velcro straps. The tape and straps hold the unit very well and allows removal if you have to replace anything in the area and need access. Easy to run the wires from the amp to the head unit as they are close in proximty. Used a plastic cable cover for the 3rd set of speaker wires to mitigate any chaffing. I ran the wires to the cockpit circular light openings. I ended up getting a big hole saw and cut speaker holes where the cockpit lights were and installed another set of 6" Fusion speakers there. I moved the cockpit lights in the same area. I ran the starboard wire along the top edge of the aft cabin, there is a trim piece held with screws that you can run it behind. I bought a face plate off Amazon to clean up the install, really don't need it as the Fusion head is almost the same size as the Kenwood. Still have a channel for subwoofer if desired. Thought about it, but the only place I could find is starboard side of the aft seat. With the 3 speakers, more than adequate for this family. Can't say enough good things about the Fusion equipment. The Kenwood speakers were cracked and beat up and the head unit had corrosion on the circuit boards. It was time for a change.
