I initially had plans to put a 139dB air horn on mine. There is plenty of room for an air tank under the hood once you remove the foam faux engine cover. However the factory horn on mine is adequate enough that I didn't bother.
I'm pretty sure I don't need an air horn, but hey that would be pretty awesome. I just ordered a set of lo/hi horns from Hella on eBay. I'll report back after I install them.
Mission accomplished. I installed the dual Hella horns today. I ran some large gauge wire to them for both the power and ground. The trigger wire(s) is easy. I removed the factory horn, cut the wires, used the instructions on the side of the box, and a couple hours later I had them working fine using the included relay. The cut wires are Blue=12V(+) Trigger, Black=(-) Ground, both go to leads on the relay. I happened to have a pigtail that plugged right into the relay, but it would have been just as easy to use female spade connectors. I soldered all my connections and should have trouble free operation. It's at least twice as loud as the stock horn was. I can't wait to go honk at somebody. :twisted: