I also installed the both horns which Topmanda has in his link.
This ones:http://item.taobao.com/item.htm?spm=...id=12610507306

The Horn is great! Loud and sounds like a CAR-Honk! (to be concret: it sounds nearly like a Original Mercedes-Benz Honk they have in their cars)

Very good Honk and really a safety-feature! U sound like a car now so everybody gets out of ur way.
Topmandas honk = Thumbs up!!!

Cheers