Great shots, Raymie. I wish I could get a chance to photograph some motorcycle racing.
As for the whole pan at slower shutter speed thing, I think it's a great effect, but doesn't need to be done all the time, as some people do. I've used it sparingly with bicycle racing, and people who are looking for pictures of themselves usually prefer the frozen action shots. In the end, it's a matter of personal preference.
For what it's worth, my favorite of these is the 4th shot on the first post.
Thanks for posting these!