I read a couple of treads on another Horn site about the Freeway Blaster and if you run two you should run a relay to get the juice to the horns that they need. Two may be too much for the orignial wiring through the switch.

05 BA, Goodwood Green, Chevy605 pipes , ai removed, Freak kit, K&N pods, 145 main/42 pilot / 3 turns out, bags and screen