Bob,
Those are stock and would be your "country" horns!
Literature points out that the Mangusta came equipped with Town and Country horns!
You should have a two position switch up on the dash that controls which one you are using!
City horn sounds like something from the Roadrunner cartoon.....air horns are the only way to fly!!!!
Check all your electrical connections up in the wheel well area before calling them bad.....! You can test them with your shop air hose too...... Compressor needs a GOOD 12V before it will honk 'em!
Steve