Thanks for reminding me. Had windshield replaced about a week ago, by shop I've used before. I loosened the cowl and installed the siren the day before, and put cowl back after glass was in. (good time to check those drains for debris clogging).
I disconnected battery ground to be safe (probably could've just removed #9 fuse). Siren went in with original bracket. Works like a charm. "Chirp" is misleading: sound is 3 soft beeps when locking & 1 when unlocked. Mrs. did not want a chirp, so she is pleased.