Did see one in Germany last weekend at a hobby fair, not running though. Nice looking track pads, and the motors are possible the same as on the KAT excavator, which are strong. Say there are 80 track pads, and buying those separately is about $200
400 for the machine is not bad..In good old 'traditional' way, there are of course very limited information and tech spec. available, but I would be surprized if this is including hydraulics. And 6 kg/ 13 lbs...well, a bit hard to believe, as the KAT guy uses 2 mm alu plates...Maybe 3 kg ? Anyway, I'm sure there are free space to put in additional steel plates to get the weight up (if there not already are)