I would skip the kits and build your own system for two reasons.
1. I don't like the setups where the compressor is attached to the tank. You're going to have a hard enough time finding a place to mount a tank, much less one with a compressor hanging off it.
2. You need at least a 3 gallon tank to power those horns. I have similar horns and they use about 75cfm.
The key to air horns is not so much the pressure, but the air volume. If you want to get the full effect of the horns you need to go with BIG tank ports, air line, and valve. I used 1/2" for everything and it made a HUGE difference over the crappy 1/4" line they give you with a kit.
I wasted a bunch of time and $$ figuring this out. If I had to do it again I'd buy the stuff separately:
Horns
3-gal tank with 1/2" ports
ViAir compressor
150psi pressure switch
1/2" I.D. hose
1/2" I.D. Valve - I used a GC Xtreme fast nitrous valve
That will get you the most from the horns. A couple second blast will drop the 3-gallon tank down 50psi and take a minute or two to refill. I can take a few pics of my setup if you're interested.
Have fun!
