I had a set of the trumpets on my deck as well. Mine was full of mud bees and rusted out internally. Found something close. I had to drill new holes for the mount as it was not the same as the OEM. As for the headliner, I did not need to cut it for the horn mount. I did for the new wires as mine...
We have. 90 310da. My tanks are on the sides of the hull in a vertical setup. I had to replace the cork Float on the port side. This was easy to do as it was in the same hatch as my power switches. The starboard side is under a access panel in the rear birth/seating area.
I was going to use marine plywood and raise the floor an inch or so myself. Looking to see how others did the curved sections on the floor. Thanks for the reply!!
We still have the blue shag carpet and the headliner is in need of TLC. I need to pull the rails off the deck and reseal the anchor points. Rub rail needs the screws pulled and resealed too. Lots of work to do, marina will not let us in due to COVID lockdown. Nice work.