Did you buy just the horns or their whole kit? That compressor/tank combo is a P.O.S. Mine blew up in the first week. They still owe me a new one and its been 3 months since I RMA'd it.
I mounted a 3 gallon tank and a Viair compressor in the jack compartment. I actually have a new tank coming with 1/2" ports to accommodate the new 1/2" line and valve I bought. The jack & stuff is under the back seat now.
Charles, did you regulate down to 70psi or do you have an adjustable pressure switch? Is there a negligible difference between 70 and say 150? I'm running 150psi to the horns right now.