"...standard kit..."
I'd be happy if I took these myself and I have a 1DmarkII
RC cars are far from easy to photograph. especially off road as it's harder to prejudge the "Line" that the car will take. Your panning looks OK and the images are sharp.
It's too easy now with the high powered motor drives to take a "cine" of the subject, find the one shot that looks OK, and "lo and behold" you are a fantastic sports photographer.....
Look forward to seeing more of you work.