yes, comparable cars from classifieds, ebay bidding, hemmings just had an article with market value, blue book etc. I would just try to overwhelm them with evidence showing the car is worth a lot.
also, it would be great to avoid the salvage title. So you would have to show the car is worth more than than the repair would be. It already sounds like you might have a lot, but borrow more reciepts for engine upgrades, transmission etc. I know it is a little shady, but I have no problem sticking it to an insurance company to save an 02.