[Steve W]

I agree with Kevin. A spare part is for replacement only. Once you attach it to the arm or whatever it is now part of the robot. Once assembled the robot must still meet weight requirements.

We must make sure that we don't try to make the rules meet our way of thinking. Rules should state the obvious. In this case you weigh in what you are going to use. If you add to the assembly then you must reweigh with ALL parts. I see no problem if you switch motors around between assemblies as that is how you weighed in.