I had a car stolen and never recovered here in BC.  ICBC (Ins. Corp. of BC) really low-balled me on the value of the vehicle.  After a month of back and forth letters, including links to ads plus my year old receipt, they upped their assessment by over 20%.
Insurance companies are not on your side and will try and snow you with fancy letters and their "intimate knowledge of the market" but if you have the facts they will move on their estimates.
If the car is "rebuilt" it is worth much less and is hard to sell.  Nobody wants them.