Al, Jim, and Will Tracy were early students of Ed Parker, starting back in the late 1950s. Later, Mr. Parker began to make changes to the art, taking it in a different direction. The Tracys didn't agree with many of these changes, so they eventually split from Mr. Parker, and established their own lineage of kenpo. They feel that they have kept their kenpo closer to how Mr. Parker first learned it from his own teacher in Hawaii.
Currently, Al Tracy heads the organization, his brothers are no longer formally involved.
The Tracys have also incorporated some elements from other arts, both Japanese and Chinese, into their method, so yes, there have been changes of their own made.
Jay T. Will was a student under the Tracys. I believe he may have also had some training under Mr. Parker, or some of Mr. Parker's other students, so I imagine there would be some of those influences in how his lineage practices their method.
Any of the kenpo methods can be a very good path to follow, if well taught and if the art speaks to you and is a good match for you.
