I just installed a 135 db Stebel horn that has the two-tone air horn sound similar to a Ferrari. I love it. It wired right up. The instructions spoke of a relay and all this, but it plugged right in. I put it in the driver's side fenderwell where the old one came out, but I want to move it more centered.
I got this one:
http://www.twistedthrottle.com/trade...view/2137/539/
You can hear them all on:
http://www.stebel.it/stebel/index2006_1.htm