ORIGINAL: controlliner
The K&B is done by a retooled TOKI dies. The rod is a phospher (spelling?)bronze rod. It is a very strong rod with a smooth ''dogbone ''shape. There are no stress risers on it compared to the aluminum rod.
Yes, you are probably right that the conrod is strong and made with good engineering considerations. I'm perhaps a little biased from discussions in the 1/2a forum where people think the weight of a bronze rod is holding the Toki .05 back.
So it seems like the HPI engine that I have is an early one, and that they since then have moved to a "thick" nickel layer and a Bronze rod on all of the engines, Toki, HPI and KB.
I will run it and see what it gives, the quality seems fine and it has a nice pinch. One thing I found, just by looking, is that the transfers ports seem to be rather blocked at BDC. The bottom of the liner bore in the case could do with some clearing out (it is better done on the HPI). This could easily be improved with a dremel though. Here are two pictures, not sure if it will show up that well (KB first, HPI next);