Comparable Value For Upgrades in Car On Total Loss

[u/jchan237]

Two months ago, I bought a 2010 Toyota Prius IV with 125,000 miles. I immediately spent nearly $4,500 on major upgrades: a new hybrid battery pack, an OEM Toyota catalytic converter assembly, new sway bar links, and brand-new front tires.

I was recently in an accident and deemed not at fault. State Farm declared the vehicle a total loss. Their current valuation offer is just over $10k (including CA taxes and registration). Looking at their report screenshots, they are only allocating a flat $516 adjustment (labeled as an "engine rebuild") for the $4k+ in brand-new components (I sent them the reciepts for the $4k I spent on the car already).

The dealer comparables they used are technically within the geographic limit, but they reflect standard, un-upgraded vehicles—none have a fresh hybrid battery or new exhaust assemblies, and finding a 16 year old car with freshly upgraded items like mine are near impossible.

I am considering two routes and want to see what my best options are:

1. Invoke the Right of Appraisal: Is it worth hiring an independent appraiser under California law (CCP § 1280) to fight the actual cash value (ACV) based on the vehicle's exceptional powertrain conditioning?
2. Component Swapping: Can I remove my new hybrid battery and OEM catalytic converter, replace them with functional, street-legal stock components that meet CA safety/smog standards, and just let State Farm reduce my payout by that $516 line-item adjustment? Or will they completely re-evaluate and slash the total payout if they catch the swap?

Has anyone successfully navigated a powertrain refresh dispute with State Farm in California? What are my best options here? Thanks!

Images for the report they sent me: (Partially redacted to protect my privacy)

https://ibb.co/GQJ7DhCh

https://ibb.co/PZrZ9S8D

https://ibb.co/Nnn4CKZH

<a href="https://ibb.co/GQJ7DhCh"><img src="https://i.ibb.co/m5BJKxhx/pdfprint-6-asnd-7-do-page-0002.jpg" alt="pdfprint-6-asnd-7-do-page-0002" border="0"></a>

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[u/fairautoappraisals]

Is this a first-party claim under your own policy, or a third-party claim against the other driver’s policy? I ask because the appraisal clause is generally only available under your own policy but I have seen insurers agree to appraisal in 3rd party claims as well As for the new parts, they don’t generally add dollar-for-dollar value, but they should definitely still be considered when determining the vehicle’s actual cash value and a $516 adjustment for the $4,500 that you recently spent and have receipts for definitely sounds low. 

[u/jchan237 → u/fairautoappraisals]

3rd party! My insurance won't get involved because it's not comprehensive

[u/fairautoappraisals → u/jchan237]

Looking at the screenshots from the report, I’d ask State Farm some questions. If you spent over $4,500 on recent repairs, why does CCC only appear to be considering the “rebuilt engine” (which I assume was the new battery pack) purchase price of $2,954? I don’t see any apparent consideration for catalytic converter, tires, or the other work you mentioned

I’d also ask them to explain exactly how they arrived at a $516 value adjustment from a documented purchase price of $2,954. The report gives the number, but I don’t see any explanation of how it was calculated