Paul, them things are loud!!! You can not hear the factory horn anymore, highly recome d it, but you have to get rhe rivco harness, i have a spare low to e if you want it, that way you need to get the low only. For some reason they sent me : instead of 2
That's funny. When I ordered my pair, they sent me two high-note Magnums (I guess you ended up with the extra low-note from my pair). When I contacted them, they were very apologetic, sent me a low horn immediately, and said to just keep the extra high-note horn.
I just installed the spare high-note on my FJR1300 in place of one of the two stock horns. Sounds much better than before.
As far as the wiring goes, I've never bought a commercially-made harness for the 4-5 times I've done higher amp horn upgrades. If you have a basic understanding of auto/MC electrical, it's pretty easy to wire these up using a Bosch-type relay and some 12 gauge wire with an inline fuse on the line between the battery and the relay. The real challenge can be connecting the horns well to a good ground.