Because you have a Britax, you might not have to replace it for some crashes.
MOST carseat manufactureres require you to replace even after a minor crash.
But sense your car is totalled, I would consider that grounds for replacing it. You can keep the cover, and if it was unoccupied, the harness too. Your insurance should buy you a new one!
Here is more info on britax (copied from somewhere on car-seat.org)
Britax's FAQ refers to the NHTSA criteria for carseat replacement after a crash at http://www.britaxusa.com/customer-se...r-seat-basics/
Q: What should I do with my child restraint that's been involved in a crash?
A: Britax recommends that use of a child restraint be discontinued if it has been in a severe crash. We further advise of the National Highway Traffic Safety Administration (NHTSA) position that it is not necessary to replace a child restraint after a minor crash. A minor crash is one that meets ALL of following criteria:
* The vehicle was able to be driven away from the crash site;
* The vehicle door nearest the child restraint was undamaged;
* There were no injuries to any of the vehicle occupants;
* The air bags (if present) did not deploy; AND
* There is no visible damage to the child restraint.
Here is the direct link to NHTSA's crashed seat criteria for replacement, previously cited by the Britax crashed seat FAQ:http://www.nhtsa.dot.gov/people/inju...raintReUse.htm
Please note that the above manufacturer's crashed seat FAQs and NHTSA criteria do not differentiate between an unoccupied and occupied seat. The carseat has been subjected to crash forces even if it was unoccupied at the time of the crash. There could be unseen damage from the stress of the crash that could potentially cause the seat to fail to properly protect your child in the event of another crash.