I know this is kind of old, but I just wanted to comment. My FIL had a Springer when he was in his late 20's (which was about 25 years ago..) that had Rage Syndrome. No sort of signs at all before it would happen. They had to put him down.
When I was really researching them, and planning to get one, I read a lot about getting a field bred ESS over a show bred, as field bred had less chances at having Rage. Whether or not that is true, I do not know. But, Rage was a major downfall to the breed, and that is why I decided to go with a Boxer...