Ex Progressive adjuster.
Just read your policy. It will be clearly written what you do if you don't agree with the value they present. Most say each party will have an appraisal done by an independent party at their own cost, and if they are equal the insurance will pay that amount. If they are not equal (likely) the 2 sides will negotiate to an agreeable number, which you then get the choice of accepting.
You can provide comps, which they may look at, but they don't have too. Since you have a policy contract with them it is their choice to try to work with you, or to require you to go down the appraisal route.
I would
1. Pull the comps. Local are better but go as far as you have too. Nice examples help but even crappy cars can prove your point once you adjust for condition and mileage.
2. Get every service record you can. Understand maintenance is a mixed bag. You are expected to do it to keep the car in a drivable state. Having some records doesent really increase the cars value, it just shows it was reasonably cared for. If you have abundant over the top records that will help your case; if you have none that will hurt your argument.
3. Do mileage and condition adjustments. Use a reputable mileage deduction (find online, cite source) like NADA to increase/reduce your cars value. Do the same for the comps. Do this to come up with 1 value that incorporates all others as a fair market value.
4. Present your cars actual value based on the comps and adjustments. Give copies of all your records.
You will get more by arguing your point, and you will definitely get more if you do so while being polite (more bees with honey).
Outside of my work experience I went down the appraisal route once for a recovered theft. My insurance company offered me 4K for my DD 94 Honda Prelude in 2006. I had done extensive work (new engine, new transmission, full body professional repaint) and had 10K in receipts. I knew it wasn't worth 10K, but I wanted 7-8 which was realistic given its condition and quality. I simply declined their offer (politely) and asked to use the appraisal clause in the contract. I hired a local appraisal company (Google it) and paid them 500 for their service. They wrote an appraisal for 10K (gotta start high) and they negotiated with the other appraiser to to 7800 (plus sales tax). I ended up with a check for about 8500 after all was said and done. It took a few weeks, but I didn't have to haggle or argue (or do anything really) so it was worth the 500 to me.
In response to the above opinions
1. They don't necessary have to pay you for custom equipment, it depends on your policy. Some cap custom parts at 500 or 1k, others don't provide coverage beyond the cost of the factory part unless you buy specific coverage. Also remember some "mods" can actually de-value your car. Taking off factory rims that cost 300/each and replacing them with 100 dollar American Racing specials from Sears adds no value to the car. Same argument can be made by insurance company that factory tape deck costs 500 and the CD player you installed was only 200. CD player is a harder argument for them to make given how much more useful a CD player is but you get the point.
2. From your description it sounds like your insurance would find you at fault, so there would not be an open BI claim (a claim where they pay you for being injured). If they provide medical coverage (med-pay or PIP benefits) they are required to provide those benefits under your policy contract. These payments are to medical providers (not you) or for wage loss (must be verifiable and required by doctor). Neither of these give you any leverage in resolving your property claim.
Feel free to ask any questions or PM if you need any help. Goodluck.
- - - Updated - - -
Thanks for the feedback guys. KBB suggested retail price is $10,255 and NADA Guides Clean Retail is $10,187. Fair market value is higher since there are very few of these cars available with low mileage. I think Hapa88 makes a good point with the NSX. This is one of those scenarios where the book value doesn't fairly represent FMV of the car. Osiris_x11 I may have to get an independent appraisal, I'll let you know how it turns out.
Just an FYI - KBB is garbage; it goes off of dealer list price (not the sales price). Especially with used cars, people don't pay dealer asking price. How much do they get negotiated down? Who knows? KBB only uses original asking price which is a very poor method of valuing a vehicle. Obviously dealers have incentive to ask high knowing it will likely be negotiated down.
NADA is much better as it is actual sales values as reported by dealerships.
Not to be discouraging, but dealer value is what a dealer can sell the vehicle for. If you read the fine print they state the car has been reconditioned by the dealer and is in great shape. You should be looking at the private party which is the expected value when a private individual sells their car.
If your car is the diamond in the rough as you say no site is going to reflect your specific cars value as most cars sold are not top 1% examples of their make and model. Most have physical or mechanical issues which is to be expected for a 15 year old car. An appraisal is the only way you're going to get close to the 12-14k value you are seeking. Unless of course they pay you for customer satisfaction reasons which is a different bag and done at their discretion (usually to keep good customers from leaving).
UPDATE #2
Not sure why but this got me in my old work mode.
One last thing to consider is how much is the damage estimate? Lets say its 7800. State Farm says total it as the damage is at 100% of the cars value (in their opinion). Flash forward and you get your 13,000 value. Well now the damage is only 60% of the cars value. Id bet state Farm would rather pay 7800 (give or take) then 13,000. As this is your contract you cant force them to do anything outside the terms of that contract, which I'm sure says something along the lines of they pay the repair value, or vehicle value, whichever is less.
Just something to think about. My insurance tried this on my theft (they said it was not a total loss at 7800). Unfortunately they had possession of the car and failed to fix/secure the window that was broken to gain entry into the car. An open vehicle in Oregon in November and December gets moldy fast. No way they were gonna buy an all new interior.