So, I have a 2007 Prius as well as my 2006 Matrix. Prius has a dual horn setup and sounds great. Matrix, on the other hand, has a single horn note and is ridiculously quiet and well... single note does not get as much attention. I would rather have a lower volume dual tone than a loud single tone or a loud dual tone. I do not want to frighten people with my horn (that can actually be dangerous and also stupid). I want my horn to be noticeable, though. I find Prius horn perfectly adequate and would love to just add a second note horn to my Matrix. Anyone done this with Toyota parts? Say a Prius horn set? I do not want to buy air horns, or super loud train horns. I want something that is made for Toyota (Denso?) and will either compliment my existing horn or replace it with a dual note set that will not require a lot of re-wiring.