Hi, I have been trying to gain a better understanding of the Dynamixel by using the AX-12A & AX18A with Wizard2.0, SDK, etc. I've learned that the MX models have a finer controls over things like PID gains. Is there anywhere I can check to buy a used MX model? This will be just for SW and running experiments, so I don't want to spend lots of money on a new one that will just sit around. Your thoughts?