Just finished installing a set of marine boat horns. Have been looking into train/truck horns for some time, but after a visit to West Marine, I decided to go with the boat horns and try them out.
From what I've been able to determine, they are less prone to corrosion, lighter, and take up less space. Granted they are electric, but that's what saves space and weight by having no direct need for a compressor or air tank.
Installed them behind the front grill not far from the factory ones, but will be activated by a separate "horn" switch discretely placed.
Ran out of day light so pics will follow tomorrow