The only thing I would change about your shots is that some of your captures have cones in front of the car, kind of a nit picky thing for me at least because my attention is always drawn right to the cone. Otherwise your panning technique is GREAT, cars are nice and sharp, I think you did an excellent job overall capturing the motion and keeping the car in focus. Also the one thing that took me a few events to learn is that moving around is a VERY good thing, but it looks like you did a fine job of that already. I would find a spot that I thought had a perfect vantage point and just not move, which makes for some very boring PP later that day haha.
phil, motorkhana's are similar to auto-x's but also very different. Motorkhana's have a lot more maneuvering involved and are frankly FAR more difficult than a typical auto-x. The states don't really have much of a following for motorkhana's which is unfortunate because they are extremely entertaining to watch and I'm sure are a blast to participate in! I think you got some great captures from the events you attended as well!