Oh well, thanks for taking one for the team Rudy. I guess that's why the German bronze ones are so expensive.
Mike, I have the 35 scale kit and I don't think their gearboxes are a good choice. They are laser cut sheet steel sandwiched together. It might do fine in the turret ring, but I doubt they'd be long for the world once there was some resistance on the track. I had robot gearboxes already and plan on sticking with them when I eventually build it. That said, I believe Clark came out with a kit for it as well, I'd take a good look at that before the scale 35.
On a side note, I got the Tamiya hand drill and it's fantastic. The collier is the same size as the ones in the Proedge pin vise, so I can chuck bits down to 0.011".