Modified car insurance

A plain-English guide to cover for modified cars

Modified car insurance is designed for vehicles that differ from their original factory specification. That might be as simple as aftermarket alloy wheels or as involved as an ECU remap, suspension changes, or a full body kit. Insurers treat modifications as changes to risk. Some raise theft likelihood, others increase accident potential or repair costs. If a modification changes the way your car looks, goes, stops, or is valued, it usually needs to be declared.

In the UK, non-disclosure is a serious issue. Over one in five vehicles are estimated to have undeclared changes, exposing drivers to claims averaging £10,000 or more if cover is voided after an at-fault crash. Among owners who know their cars are modified, around 27% admit they have not declared those changes. In the worst cases, serious incidents can exceed £50,000 in costs, which the driver may have to pay personally if the policy is void.

This guide explains what modified car insurance covers, how it works, and how to avoid common pitfalls. We outline the types of modifications that can affect premiums, the documents you may need, and when specialist insurers could offer better value or agreed-value cover. We also set realistic expectations on price - for example, many drivers see premium increases after modifications, with the greatest rises linked to performance upgrades and high-risk models, and city drivers often paying the most.

Insurance can offer real financial protection, but only when you understand what is covered and where the gaps are. The goal here is clarity. No jargon, no scare tactics - just the facts you need to make safe, informed decisions.

Transparency protects your cover. Declare every modification, however small.

What is typically covered and how claims work

Most modified car policies start with the familiar elements of comprehensive cover - third-party liability, accidental damage, fire, and theft - then assess how your declared modifications change risk and cost. If your car is stolen or written off, valid disclosure helps ensure the claim reflects the vehicle in its modified state. Some policies can include new-for-old parts or like-for-like replacement for specific mods, but many will specify market value unless you have agreed-value terms.

Exclusions often centre on undeclared or illegal modifications. For example, excessively dark tints breaching UK law could lead to reduced or refused claims. Performance upgrades like ECU remaps, turbo changes, or exhaust modifications are usually insurable if disclosed, but may carry higher premiums and security conditions. Cosmetic changes such as wheels, body kits, and wraps are usually acceptable when declared and legally compliant. Track use, timed events, and competition driving are commonly excluded unless you buy specialist cover.

Claims follow the standard process: report the incident promptly, provide evidence of declared modifications, and cooperate with inspections. If you have receipts and photographs showing the mods and their value, settlement is smoother. Disputes often arise around non-disclosure or unapproved alterations, so keeping your policy up to date after every change is essential. In short, disclosure, documentation, and legal compliance underpin successful claims.

Who benefits most - and when it may not be needed

Modified car insurance suits drivers whose vehicles have changes affecting appearance, performance, handling, audio, lighting, security, or value. It is especially relevant if you have performance upgrades, extensive cosmetic work, or high-value parts that would be costly to replace. Owners in urban areas such as London, Manchester, and Birmingham often benefit from tailored policies that reflect higher theft risk and repair costs.

If your car is entirely stock, or if your only changes are manufacturer-approved accessories fitted by a main dealer at purchase, standard insurance may be adequate. That said, even minor alterations like aftermarket wheels or legally compliant tints still need to be declared. If you plan future modifications, tell your insurer early so you can understand likely costs and any security requirements before spending money.

Choosing a level of protection

1. Basic - third party, fire and theft

   • Covers damage you cause to others, plus fire and theft of your car.
   • Usually excludes your own accidental damage and many modification replacement costs.
   • Suitable only if budget is tight and your mods are limited and low value.

2. Standard comprehensive

   • Covers third-party liability plus accidental damage to your car.
   • Modifications are covered if disclosed and legal, often at market value.
   • May require enhanced security for performance or theft-prone mods.

3. Comprehensive with like-for-like parts

   • Attempts to replace declared parts with similar quality items.
   • Useful for specialist wheels, suspension, or exhausts where standard parts are inappropriate.
   • Check limits, approved repairers, and whether labour rates for specialist work are covered.

4. Agreed-value comprehensive

   • Sets a fixed insured value that reflects the car with its modifications.
   • Helpful for high-value or extensively modified vehicles where market value would underpay.
   • Requires evidence - photos, receipts, valuations - and periodic reviews.

5. Optional add-ons

   • Protected no-claims discount - preserves your NCD after an at-fault claim within limits.
   • Key cover and enhanced courtesy car - useful if specialist parts delay repairs.
   • Legal expenses - assists with uninsured losses recovery after non-fault incidents.
   • Breakdown cover - consider for lowered or performance cars that need specialist recovery.

What it might cost and why prices vary

Prices vary by insurer. Many drivers see up to a 16% increase after modifications, especially for performance upgrades. Cosmetic-only changes may add little, but every modification must be disclosed to keep cover valid.

Who can apply and what insurers expect

Most UK drivers with a valid licence, a roadworthy vehicle, and legal modifications can apply. Insurers will ask for full details of every change from factory spec - parts, brands, dates fitted, and who performed the work. Photos and receipts improve accuracy and help with valuations. For high-value builds, a professional valuation or engineer’s report may be required.

Common reasons for decline include undeclared or illegal modifications, past policy cancellations, serious motoring convictions, very high performance tuning without supporting security upgrades, or an absence of evidence for claimed parts. If standard insurers price your risk very high or decline, a specialist modified car insurer may offer tailored terms such as agreed value or like-for-like parts.

From quote to claim - the simple path

1. List every modification with dates, receipts, and clear photos.
2. Get quotes from both standard and specialist modified insurers.
3. Compare cover types - market value, like-for-like, or agreed value.
4. Check security conditions and consider trackers or immobilisers if required.
5. Buy the policy and keep proof of declared modifications on file.
6. Update your insurer immediately before fitting any new modifications.
7. If an incident occurs, report it quickly and provide evidence.
8. Cooperate with inspections and repair networks to speed settlement.

Advantages and watch-outs

Key checks before you purchase

Read the policy schedule and endorsements carefully. Confirm whether your settlement is market value, like-for-like parts, or agreed value, and how depreciation is handled. Check excesses for theft and accidental damage, plus any higher excesses applied to young drivers or specific modifications. Understand exclusions around track use, illegal parts, and undeclared changes. Look at courtesy car provisions, repairer networks, and whether specialist labour rates are covered. Finally, review renewal terms and how future modifications must be reported to avoid accidental non-disclosure.

Alternatives if this is not quite right

1. Standard comprehensive car insurance - suitable for unmodified factory-spec vehicles.
2. Classic car insurance - for older, limited-mileage cars with sympathetic upgrades.
3. Telematics insurance - can help younger drivers manage costs on lightly modified cars.
4. Temporary car insurance - short-term cover while buying or selling parts or cars.
5. Track day insurance - separate cover for closed-circuit use not covered by road policies.

Frequently asked questions

Q: Do I need to declare minor cosmetic changes like window tints or wraps? A: Yes. All modifications must be declared, even legal cosmetic ones. Legal tints are usually insurable, but undeclared changes can risk refusal or reduced claims.

Q: How much more will I pay after modifications? A: It varies. Many drivers see increases up to 16%, especially for performance upgrades and in major cities. Cosmetic-only changes may add little, but there are no guarantees.

Q: What happens if I do not disclose modifications? A: Insurers can void the policy for non-disclosure. You could face claims personally, often £10,000 or more, and serious incidents can exceed £50,000. Fines may also apply.

Q: When is agreed-value cover worth it? A: When the car’s true worth with modifications is not reflected by market value. It is common for high-value builds or rare parts where replacement cost is significantly above book price.

Q: Are young drivers penalised more for modified cars? A: Usually, yes. Young drivers already have higher risk profiles, and modifications add further risk. Annual premiums over £2,000 are common for under 25s with modified vehicles.

Q: Do certain models cost more to insure when modified? A: Yes. High-theft or high-performance models like premium SUVs and hot hatches have seen sharp premium rises, driven by theft rates, repair complexity, and performance risk.

Q: Will extra security help reduce my premium? A: Often, yes. Thatcham-approved alarms, immobilisers, trackers, and secure parking can help. Some policies require security upgrades for performance or high-value modifications.

What to do now

If your car has been modified, gather your documentation and list every change. Compare quotes from standard and specialist providers, checking the settlement basis and any security requirements. Take your time, ask questions, and choose cover that reflects the car you actually drive. You are in control - clarity and full disclosure will keep your protection intact.

Important information

This guide provides general information, not personal financial advice. Policy terms and pricing vary by insurer. Always check the wording, endorsements, and exclusions carefully, and ensure all modifications are legal and fully declared before you buy.