I dont know about the other subforums here on TMC, but the model 3 section has had "very" little member to member support for people with salvage model 3s.
I think the model S subform here has a more robust support because its a much older platforum, but there is very little discussion about people self repairing / re building these cars here on TMC, at least as of yet.
Perhaps when you find the answer, you can be one of the first to start relaying this information to others.