I love these horns, here is a DIY.
First off you will need to remove the plastic panels above the radiator exposing the stock horns. The panels are held with clips and pop out.
Next remove the stock horns, the new trumpets fit best facing the passenger headlight.
To mount the new trumpets you will need longer mounting screws and several washers, the bell on the new trumpet hits the stock bracket causing the trumpet to rotate as you tighten the bolt resulting in an insecure mount. By using a longer bolt and washers you lower the trumpet on the bracket and the bell no longer hits it allowing for a very tight solid mount, I used a bolt about double the length of the supplied bolt. Take it to the hardware store to make sure you get the right size threads and diameter, you might buy a few lengths and return the unused ones, cheap enough to keep in the tool box.
I mounted the compressor in the passenger fender well using a shelf bracket, make sure you use lock washers for this. See pics.
I routed the air hose thrugh an opening in the headlight region, just find a hole, you don't want to go over the bulkhead, may compress the hose and looks unprofessional.
Wiring is easy, save some labor and try this first, I think you only need to run one wire to the compressor since it is an electrical signal and the compressor will send air to both trumpets. I thought of that after I did my wiring. I spliced the two horn wires (again I don't think that was necessary) and ran the stock fitting to + terminal on the compressor and ran a ground wire from the - to the ground nut near the compressor at the fender.
I don't like the horn chirp when locking my doors , the chirp does not signal the compressor hard enough to blow the trumpets, you can hear the compressor click but it is wasteful if the horn doesn't chirp and adds wear to the compressor so I turned that feature to the off position on the EVIC