I have an air horn setup on my Gix 7fiddy and it is fricken loud. Bascially you can go to a local auto parts place and pick up a set for 15-30 dollars. I got a FIAM at pepboys and I am thinking it was around 20. Remove the tail plastic and mount the horn to the sub frame, so it is not showing when the plastic is back on. It will come with a wiring diagram, so basically follow that.....it may tell you to hook it to a switch.....some people add this, I bypassed it and hooked it to existing horn button....took the wires off the existing horn and connected the power side to the wire to the air compressor and taped off the other side. For the compressor, it is about the size of a can of Campbells soup, I had a perfect fit spot in the under plastic that slide next to the battery yet is isolated from touching it. After you wire...find a spot for the compressor....and mount the horn....then you need to route the air hoses, which is simple. The whole setup is simple.....the kits do usually come with 2 of them...1 horn is plenty, just toss the 2nd one aside.