That's exactly what I would like too do. I liked the way my Toyota chirped.

I think it would require picking up the signal from the security module that triggers the horn. Then change it to fire a separate unit, instead of the horn.
Maybe the guys doing the window down mod might know more.

<font color=blue>04 Silverstone G35, 5AT, Prem, Aero
ES100 225/45-18 front 245/40-18 rear
Borla TD, Z-tube, Eibach, 35%Tints</font color=blue>

 

Do you have the Coupe or the Sedan?

2003.5 G35S 5AT Leather Package <font color=green>Emerald Green</font color=green>
<font color=red>Long Island NY</font color=red>Z-Tube - K&N - Grounded

 

I have a coupe.
But ....all you had to do was click on my user name and you would have even had pics to answer your question.
LOL

"I like you.....You remind me of myself when I was young and foolish"