They also have the Hella electric horns. They are LOUD. At least 2 - 3X louder that the horn in my coupe. I have not heard the air horn before. Cal them, they have always been very helpful to me. If it sounds like the horn from my 355 I will get one. I think the car needs something that does not sound like it came from Detroit.
If you did not know, decibels use a logrythmic(spell) calculation so every ten decibels you can count on the sound doubling in intensity.
20dB to 30dB = 2x
20dB to 40dB = 4x
Here is what the description says:
"139 dB at 4 feet, 115dB at 6 feet"