Dear milo k:
A few ideas: (1) Contact an auto adjuster from YOUR insurance company and pow-wow with him/her; they know the industry and, if there's a way around this, they should know. (2) Ask the other driver's insurance company which "book" they're using. Then go to your local library or auto dealership and take a look at other "books" to find one more favorable to you. (3) Submit documentation to this carrier showing why your car is more valuable than what they're offering (ie, receipts of extras; an informal estimate from a local car enthusiast's club; an estimate from another auto adjuster <which may cost you a few dollars depending on your negotiating skills>.) (4) Talk to the person who normally does repairs on your cars; they may be able to help you find appropriate contacts. Best of luck to you.