I contacted Tamiya customer service in Japan yesterday to request part number for 12 mm front hex hub for DB-01 RRR. Guess what they said. It is available only as part of the kit and they don't know if it ill ever be available separately as an OEM part. So, back to the original question. Which 12mm front hex hub should I get? I know Active Hobby used to make one but it's been discontinued. Any suggestion?