1. Have a list of what similar condition cars are going for (aim high ). Get it from Corral, Auto Trader, whatever, but don't bring a list of shitboxes.

2. Have a itemized list of mods.. As others have said it will depend upon the insurance company and what they are willing to pay. Some pay out a lot some will try to break it off in your arse. They are not going to care about oil changes, upkeep, etc.. They view that as maintenance.

3. Shoot higher than what you are looking for because they are going to undercut everything.

4. Last but not least and this applies to any sale, negotiation, settlement (at least from what I have learned over the years). Thee who names a price first gets hosed 90% of the time in the end. Let them offer, then you shoot back much higher, and settle somewhere in between. This is the same thing I do with contract negotiations on homes and it works just about every time.

Just don't let them bully you into something you are not comfortable with. Like Figment says they have to pay your rental while they are dicking around. And as much as I dislike attorneys the threat of using one after all else has failed is a wake up call to some.

Good luck, keep us up to date.