I got my compustar 2 way alarm / start back about 2 months ago and love it! Well since i got , i always wanted to hook up a loud horn to it, but not quite the shockers… so i bought a psychoblaster and hooked it up! Today i went back to my audio shop (darrelys car audio in buffalo ny) and they hooked it up to the aux function on remote , and tapped into the siren! So now if i want to just activate the horn i go thru aux , and it gives a good blast. (enough to scare someone away) or if the alarm goes off, the siren / stock horn / and psychos go off all at once! But because they are so high, u can only hear those, lol. I also had them put it on a switch so i can trun off the psychos at night in case of a false alarm so i dont wake up whole neighbor hood! 
heres some vids i took earlier. Unfortunately my camera is terrible for video / sound… but u got the idea…
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Startup with the 2 way… notice how how it alerts you
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Heres the flows… camera does no justice!
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