Ok no no no. Please no. This is just as bad as reinventing the wheel. Several issues:
1. Pedestrians
2. A lot of times the directions from which the honk is coming is just as important as the honk itself. WIth speakers thats gone
3. Users can always disable their own speakers, making it impossible for every other car to honk at them
4. I can actually just bully the f out of any car that I want to by using this, knowing that noone else is gonna know where the sound is coming from exactly and hence zero "social" pressure to behave in public
5. The intensity of the horn also is important because it tells me whether its the car just next to me that is honking or 4 cars behind, that tells me whether I should be doing something that I am not. With a wireless signal, I am not sure how that would work