I'm in the process of doing the same thing. I have already ordered the Tesla wall charger. I was planning to run about 75' of #6 wire off a 60 Amp breaker in my panel. Even though I have a 200A service panel, I might be overloaded and not able to install a charger with the current panel configuration. I called the Building and Safety people (They issue the permit) and they are working with me to identify what I need to do to complete the installation. I like to spec out all the details of a project before bringing in a contractor to do the work. If all goes well, I might do the work myself. If I need another power panel, I'm screwed, as the cost will be much more than I had planned. I think it is pretty important to get a permit because there is a lot that can go wrong with 240V!