Marc! pop ERASE into the search hopper and read his saga in dealing with an Insurance company getting full value on a policy where he did NOT have a "Stated Value" Rider.

I quickly read the past posts up to this one so if this was already suggested - my apologies.

Not a good idea to keep the car unless you are planning on KTIC-Keeping Till It Croaks.

If you were to go onto carfax.com - input your vin and pay the $14 fee to peek - you may see that they already have the damage report to your vehicle. Any potential purchaser or Wholesaler is most assuredly going to pull a history on the vehicle.

Ask your dealership to give you a price in writing to buy the car back from you. Whatever the difference is in what you originally paid including your trade-in 300E and what they offer you is what the insurance company is only going to be required to pay.
You currently have no basis in fact of what that amount is. Going in front of a judge without that would almost assuredly guarantee a lose. The amount already paid by the ins carrier may already be enough to make you "whole". It may also be substantially less. At present, you do not have a foundation for your case that is rock solid. If I were an atty, I would be taking this case strictly on hourly with an up-front retainer, certainly not contingency.

Get written offer to purchase your car from your dealership or any registered/licensed dealer and then you will have a document establishing a basis in fact to go to the insurance company with and threaten litigation or payment to avoid same.

There is a hidden benefit here that I am not willing to put on an open forum. Email me if you do not see it.

Tom