# 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.

Source: https://modvault.com.au/guides/modified-car-insurance-australia/
Last checked: 2026-08-24

## 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.

## 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.

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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.