It's not just the dog who needs to be evaluated and trained, it's the dog and the human and their interaction and relationship that needs evaluation and fine-tuning with the help of someone who understands this.
I totally agree with this.
I guess what bothers me about the OP, is the comment, the dog goes ballistic, and actually tried to "attack the car" the boyfriend was in?
I have had GSD's "forever",,and all of the ones I"ve had, will alert bark, race for the door if someone comes (stranger or friend), that in itself is a big deterrent to someone who doesn't know them.
They have never gone "ballistic" tho, they tend to be pretty good judges of character. As soon as I say "enough",,it's done, you can walk in, they may sniff you for a second and be done with it.
Zoom, I find your trainers ideas interesting and something to think about.
I had one fear biter GSD, I wouldn't say he was 'fear aggressive' , but he wasn't a turn tail and run kinda dog either. His "thing" was, if a man (stranger) came to my door, he'd be rightthere, barking, IF said "man" walked in,,for example, ya know how your parents always told ya, let him sniff your hand? IF that "man" did that, he'd sniff, as soon as you pulled your hand back, he'd nail you and back off. IF however, he was totally ignored by said "man",,no eye contact NOTHING, he'd end up in their lap...(all 125lbs of him)
He definately had his quirks, but he functioned normally in public, well on a leash, (I think leash made him feel safe), ok with other dogs, etc.
In the end I know his "quirk" was fear based, but I had never really thought about getting past the fear, and going right into aggression with the 'bite'.
Diane