Do your home work into its pedigree and genetics, they can be a great dog, a pain in the ass dog, a dog full of hereditary diseases such as hip / elbow dysplasia, eye problems, temperament problems, be sure to define between the genetics of a working dog and a pet dog, both are trainable, some more drivey than others.
A working line GSD bred for working protection, guard prey or defense, is not a pet dog by any means at all, and most owners would be wanting to either sell it, give it away, or shoot it by the time its 18 months old.
Its kinda like driving a ferrari testarossa to the supermarket or diy store, its possible but not practical
Be sure to do your home work, and be sure you get what you really need, not what you really want but don't need!
I have a contact for working shepherds and malis in Slovakia he trains them and ships world wide. But just be careful what you wish for, sometimes you might just get lucky and get it !!!