I called the two places in MA that Torklift listed as installers, and neither had ever done one before. U-Haul really butchered my Subaru when they put in a hitch. (I had to have a shield panel and the wiring replaced by the dealer after quick failures. I'm glad it worked for you, but I don't think I'd trust them with my Tesla.
I also did my own EcoHitch install - took me a couple days between sorting out all the tools/tweaking I needed to do... but it's always satisfying to do it yourself! And - I'll never argue AGAINST an opportunity to buy new tools ;-) haha