Modified car insurance: disclosure, proof and agreed value
Australian insurers require modifications to be disclosed, and can reduce or refuse a claim where undisclosed modifications are found. Engineering certificates, parts receipts and dated build photographs are the evidence that supports both disclosure and an agreed-value valuation.
Disclosure is not optional
Every modification that changes the vehicle's performance, safety systems or value should be disclosed. This includes the ones that do not require engineering certification — a tune, a wheel package, an exhaust. The cost of disclosure is a slightly higher premium. The cost of non-disclosure is discovered after a claim.
What insurers actually want to see
- An itemised list of modifications with dates
- Receipts establishing the real spend, not an estimate
- Engineering certificates or modification plate references where applicable
- Photographs showing the work and its current condition
- Who performed the work, and their credentials
Agreed value depends on your paperwork
For modified and classic vehicles, agreed value is negotiated on evidence. A folder of dated receipts and photographs supports a materially higher valuation than a verbal description of a $60,000 build. This is the single highest-dollar reason to keep a complete record from day one.
Heritage and classic vehicles
For classic vehicles, provenance is valuation. Decades of service history, restoration receipts, period photographs and certificates support agreed-value cover and concours judging alike. Records that exist only as a physical folder in a shed are one flood or fire away from being gone with the car.
Proof, in one tap
ModVault keeps every modification, certificate, receipt and service record in one tamper-evident vault — producible roadside, at inspection, at claim time and at sale.
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Frequently asked questions
Do I have to tell my insurer about an ECU tune?
Yes. A tune changes vehicle performance and is a disclosable modification even where no engineering certificate is required.
Can an insurer refuse a claim over modifications?
Insurers can reduce or refuse claims where undisclosed modifications are relevant to the loss. Disclosure and documentation are the protection.
How do I get agreed value on a modified car?
Provide an itemised modification list with receipts, certificates and photographs. Agreed value is negotiated on evidence, so the quality of your records directly affects the figure.
Keep reading
Current as at 2026-08-24. Reviewed every 90 days; next review due 2026-11-22. This guide is general information for Australian vehicle owners, not legal or engineering advice. Requirements change and are applied at the discretion of your state authority. Always confirm with your road authority or a licensed certifier before starting work.