I'm not sure if this is the correct forum for this question, but it seemed closest related to what I was asking. I have a part that I'd like to be able to "upgrade" as you unlock nodes in the R&D tree. I could simply add in multiple versions of the part that unlock at different nodes, but then you run into linearity issues ("what if I've unlocked this node but not this node?", etc.). Additionally, I'd like to avoid having more than one part in the mix for simplicity's sake. For someone completely unversed in plugin development (or programming in general, really), is there a way of accomplishing what I described? EDIT: I should note, I was inspired by MechJeb's user experience, how MechJeb has a controller that determines what you have researched and unlocks the correct modules accordingly independent of the part itself, but I had a hard time making sense of exactly how this was accomplished from MechJeb's source. EDIT2: Found a possible solution via a post I missed during my searches by Merill.