If you can, get an attorney to assist you with this. If you want the most money out of this accident, it is going to be in your best interest to let the insurance company total out the car and give you fair market value for the parts (it's bs imo, but since you don't have receipts its gonna be tough) if you go back to salvage parts just be aware the insurance compound will document you came to remove parts and that can be dangerous and go against you. But overall count your bessings that you are alive and will heal. Again, don't worry about the parts, the car is a loss and you can always rebuild...better! I wish you the best!