This is why you should get an attorney who specializes in accidents
and diminished value to represent you.
Of course the body shop is going to tell you they can fix the car so they can bill the insurance company for likely around $20,000 of work. The body shop's interest here is being able to bill someone for the repair not making sure you are whole.
What are you going to do when parts are delayed month after month? When they tear down the car and find extra damage and again wait for more part delays? What if the car doesn't drive the same after waiting 4 months? And what about the $15-20K in diminished value?
Someone just cost you about $15-20K in diminished value and took your car away from you for most likely about 3-4 months of repairs. Why should you drive a Maxima for 4 months due to someone else's negligence? You can't let the other insurance company dictate terms to you. The total loss for you is around or over $50K after you add up accident damage, diminished value, and what it would cost to rent a Model S for about 4 months. I would absolutely spend a few thousand dollars on an attorney to make sure I'm made whole if someone cost me a loss in this range.
Do you have any back pain from the accident at all? If you do, it becomes a personal injury situation and you'll have a much easier time getting an attorney to represent you. If it were me, this is what I would do.
+ If I had any back pain or other injury, I would mention that and document your pain during an examination with a doctor. Could be as simple as stating you have back pain, have difficulty bending down, sleeping, etc.,
+ Go on Turo and look up how much a Model S P100D will cost to rent and let the insurance company know you want a Model S P100D to drive while you wait for a resolution. If they bring up a Maxima, tell them you would have bought a Maxima if you wanted to drive one. This way they will be liable for that cost each day they drag settling the claim as it will cost them the daily cost of a Model S rental. Alternatively they can find you another Model S P100D to drive.
+ Since the car is so new, you have the maximum benefit of Diminished Value. Get a Diminished Value estimate and make this a part of your claim.
Tesla Model S Appraisal Clause Dispute ⋆ Petty Details - Diminished Value Experts
+ They also need to cover the cost of the repair which I bet will be over $20K.
You should make it more financially advantageous for them to give you a check for a replacement car than going the repair route. An experienced lawyer can help with this. If you can get them to give you a check for a new car, you'll be back in a Model S P100D within 1-3 weeks by buying an inventory car and you can put this mess behind you. Otherwise it will be 4 months of frustration and hassle to get your car back in who knows what condition.
Here's another way to present the situation
Scenario 1 - Costs insurance company $50K. You are back in a P100D in 1-3 weeks.
They give you a check for a replacement Model S P100D plus tax so you can buy a new car. Will likely cost them around $110K.
But they get to keep your Model S, which would likely be worth at least around $60K with the damage so they are out by the amount of the difference. You can agree to not pursue additional claims, assuming you have no injury or other future issue.
Scenario 2 - Costs insurance company at least around $60K and possibly more
Pay you for Diminished Value: $15-20K
Pay you for any pain and suffering: $10-25K or more (if applicable and you are injured)
Pay for the repair: $20-25K (could easily be higher)
Pay for a Model S P100D rental: At least 5K a month for likely at least 3 months: $15K
You can easily make the argument that it is in everyone's best interest for them to settle with you rather than be liable for significantly more damages after you hire an attorney.
Disclaimer: I'm not an attorney and this is just my opinion on what I would do. If I were me, I would have an attorney handle this situation. The insurance company may stop with BS and want to settle as quickly as possible as soon as they know you are being represented by an attorney.
The insurance company may opt to settle with you quickly so they don't risk a much greater loss with your attorney involved and you could possibly also have the insurance company pay your attorney fees as well, if they disagree to a reasonable settlement necessitating representation for you.