Start specific, not general
"This feels low" rarely moves a claim forward on its own. "The report lists my trim as the base model, but the vehicle has the upgraded package — here's the window sticker" does. Specificity is what separates a dispute that gets resolved from one that stalls.
Build your comparable set
Pull several currently-listed vehicles that are genuinely comparable — same year, make, model, similar trim and mileage, and from a market similar to yours. Save the listings (screenshot or print) since online listings disappear.
Document condition and options
Photos from before the loss, maintenance records, and a list of factory-installed options all support a higher valuation when the insurer's report understates them.
Communicate your disagreement clearly
Put your position in writing, reference the specific report, attach your comparables and documentation, and ask for a response. This creates a record and is generally more effective than a series of phone calls.
Escalate through independent appraisal if needed
If the insurer doesn't move after a well-documented request, an independent valuation review — and, where available, a formal policy appraisal clause — are the next steps.