Go to
www.hornblasters.com they have some good stuff there as well. I have a set of 78' Buick Park Avenue Horns on mine along with the Factory Driver side one as the passenger side one was worn out. It's loud it almost sounds like a Caddy Fleetwood. Very attention getting.
My Wife's Subaru came with just a lousy little horn so I installed a set of the "Italian Car" air horns. It just has a compressor that when powered blows enough air to set the horns off. That's loud too and it sounds kinda cool too...
The bonus about both of these setups is that I didn't have to add any extra wiring just used the Factory horn wiring and relay and there is plenty of jam for both setups...
Let me know if you want me to record them for yah? I could hook up a mic and try and record them if your interested???