Proves nothing beyond what those particular cars were made to do on that particular day. In those days it was common practice for the OEM's to hand build magazine test cars. They were built in such a way as to perform better to much better then the off-the-assembly-line product ever could or would. Not convinced that sort of thing doesn't still happen today.
As I've said, I've no experience with the K-H calipers, but their formula is a better formula than the later sliding calipers. I've also not said that sliding calipers are a bad choice, just that they are not the best performance choice.
