Some points to ponder:
1. Is the vehicle titled as 'salvage, project, or Restoration'? Who labeled this car and how/why?
2. Or is it titled as DeTomaso Pantera? ...Or is it a 'PARTS CAR' where each part on the vehicle has an intrinsic inventory value? The door has a resale value. Or vehicle art? Your an artist, right?
3. The car was shipped "AS-IS"......It SHOULD have arrived at its destination, off of the truck in the same "AS-IS" condition as shipped (origin)!! It is no longer in its "AS-IS" condition. Refer to #5754's comments earlier, I fully agree.
4. There is NOTHING either party can sign that will absolve someone of negligence or gross misconduct when such an act causes material damage, physical injury or death.
5. Your pictures speak volumes. Also, I am not sure but I believe the drivers foot attire would not pass the courts, or insurance companies muster. I do not believe it is even legal to drive a vehicle in florida wearing flip flops!
6. Your offer to help was refused due to insurance reasons. IF you were allowed to help, the odds of this damage would have been greatly reduced at a minimum. This puts the carrier and their insurance back into the liability pool.
7. The way I see it there are four, maybe five parties in this conflict: You as the victim, carriers insurance co., the carrier, the driver. I would name all...or file separate suits..shotgun it. The driver has his own personal insurance to cover himself and any vehicle he drives most likely.
Personally, I would not let them drive away happily with your money leaving you with damaged goods. Just the aggravation of them going to court to defend themselves should be incentive enough for them to make a settlement offer at least. Their attorney costs would most likely be more than the claim is worth! You have to decide if the time and cost to file suit is worth the return. Your choice in the end.
The above is my opinion only and not to be taken as legal advice or direction.