Most cars, even in a seaside town, don't need that level of wiring protection. I had a commercial fishing boats for many years and used marine grade connectors on all my wiring. These were usually brass terminals ( male/female, spade, butt splice, etc.) or fittings with a heat shrink plastic coating that would become "moisture proof" when heated with a heat gun. I also soldered connections where possible. You can now buy marine grade electrical fittings on line or at marine stores, such as West Marine. Don't overlook the distriution panel if you're cleaning up a mess. On our fiberglass cars, much like a boat, the ground is very important and can be the cause of intermittent electrical problems.