How should an insurance company value the aftermarket upgrades on a vehicle?

Well, what exactly do you mean 'value'? Are you asking in the event of a total loss how would that add to the value of the vehicle? This is really subjective, say you put fancy after market headlamps in your vehicle that cost you alot, does that add to the value? not really, as long as the headlamps work. If you could be more specific as to what parts and what you mean by value I'm sure I could help you out with your question.

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