Shutzhund training is extensive. Very good for the dog, very hard on the owner.

Before you get into this sort of training, you need to have obedience done, with a minimum stay time of 3 minutes.

The best way to figure if your pup will be good at it is to have someone do an evaluation. If he is one of those "fear aggressive" or unstable temperamented dogs, then he becomes a danger to those around him.

It's very good training requireing lots of discipline. Look into it, can't hurt.

ps. If your pup is that unpredictable, IMO he needs to be put down. Unstability and unpredictability can lead to law suits against you if something happens to someone.