Problem 1: The companies that offer insurance based on mileage and safety score have much lower rates (if you don't drive a lot of miles). But they require you plug in a nanny to the ODB II port and Tesla doesn't have one, as such. State Farm quoted me the same rate for a Tesla as my Kia that I traded for it. They even added the Tesla to my policy so it would be covered when I picked it up. Then as soon as the deal closed and I dropped the Kia, State Farm then informed me that my insurance would actually be 20x the cost they originally quoted me. Yes, you can install an aftermarket ODB II port which work just fine, but then still won't offer the mileage / safety based rate on a Tesla? And of course Tesla will fight any warranty claim because of the mod, which could tragic.
Problem 2: Having got Tesla insurance anyway, you will find that their Safety Score software is even more buggy than their windshield wiper and headlight software. It will lower your score by 5 points for going through Burger King drive through. It will lower your safety score another 5 points for following too closely if you move the car out of the garage, whether or not there is even another car in sight. When the car attempts some evasive maneuver because it thought it saw a shadow and lunges into the oncoming traffic lane and you have to brake at least half as hard as the car routinely does, it will ding you another 5 points for 60% hard braking. In Texas, but apparently not in California, each point is another 10% or so on your premium, so it can quickly climb to much more than even State Farm's gouge.
On the good side, Tesla does not use the State Farm software. It has the interesting feature of combing the Texas DPS data base looking for licensed drivers who live at the same address as you and are NOT insured with State Farm and if it finds any matches, automatically adds them to your policy, with or without your consent, even against your specific instructions and increases your premium. The catch is that State Farm modifies the Texas DPS address, before testing for a match, e.g., if your address is 1234 Main Street, Apt 273, San Antonio Texas 78245 - - State farm will truncate the apartment number, changing the addresses to 1234 Main Street, San Antonio Texas 78245. Then every licensed driver who lives in that building, but is not insured with State Farm will be added to your policy. State Farm's story is, this is forced upon them by federal law and they are helpless to do anything about it. (With legal action it is possible to cancel and get a full refund.)