The brief horn beep when hooking the battery up is the security horn located in the trunk on the passenger side behind carpet trim. Normal for the beep when you hook the battery up.
With the key turned to the on position ( engine not running ) do you have a service engine soon light on? the...
That thing was fricken loud before !!!! neighbors are going to hate you.........Awesome dudes !
I wonder where you got those hangers from ? lol I need to move up there and get involved :)