I've also mounted one. It is great fun! But beware: In the Netherlands such a sound is forbidden for everyday use and the car wil not get through the MOT!! So always keep the original horn!
When I bought our +4 in the UK, there was already one on the car. I changed it for a standard one to import the car in Belgium. Afterwards I re-installed the Ahoogah horn and had no problems getting it MOT-ed. Love the sound
