I'm not sure you can change a dogs day to day personality, but I certainly believe you can mold proper behaviors and expectations during training and testing atmospheres. I thinks it's important to note that these high drive dogs HAVE to have an outlet. You have to train for balance, and develop expectations of when its time to go, and when it's time to "not go"
I have a 16 month old that can get pretty darn high,but can turn it off in an instant, and stare a hole through you waiting on the next command. If you can harness this drive, and get the dog to engage you, then you got a dog that is a blast to train!
Bill Hillmann has some excellent material about developing that contrast between hot and cold.
Check out this video. It deals with steadiness, but he talks about how to develop the on and off.