Modified Car Insurance
Car modification is part of UK motoring culture—from alloy wheels and body kits to engine remaps and turbo upgrades. Whilst modifications enhance driving enjoyment, they create insurance challenges. Failing to declare changes can void your policy entirely.
Why Disclosure Matters
Legal Compliance
Undeclared modifications can result in uninsured status under the Road Traffic Act 1988.
Claim Protection
Full disclosure ensures claims are considered under the actual risk insured—no nasty surprises.
Accurate Valuation
Modifications affect vehicle value—proper declaration ensures correct settlement amounts.
Peace of Mind
Recognition of your performance or cosmetic changes with appropriate cover levels.
What Counts as a Modification?
Insurers define a modification as any change from the manufacturer's standard specification. This includes:
Cosmetic Changes
Body kits, alloy wheels, spoilers, tinted windows, wraps, and paint changes.
Performance Upgrades
ECU remaps, turbochargers, exhaust systems, suspension, and brake upgrades.
Audio & Electrical
Enhanced sound systems, custom lighting, head units, and cameras.
Utility & Safety
Tow bars, roof racks, parking sensors, wheelchair adaptations, roll cages.
Rule of thumb: If in doubt, disclose. Transparency lets insurers assess risk correctly and avoids disputes at claim time.
Legal Framework
Road Traffic Act 1988
Requires all vehicles to be insured. Undeclared modifications may result in uninsured status.
Construction & Use Regulations
Some modifications must meet safety standards—lighting, exhaust noise, glazing tints.
MOT Requirements
Modified cars must still pass MOT. Illegal tints, non-E-marked lights, or DPF removal cause failures.
DVLA Notification
Certain modifications must be declared—engine swaps, colour changes, and major conversions.
How Modifications Affect Premiums
Performance Upgrades
ECU remaps, turbos, and exhaust changes increase acceleration and claim severity. Premiums and excesses typically rise.
Wheels & Tyres
Larger wheels and aggressive offsets alter load ratings. Insurers require tyres meeting manufacturer specs.
Bodywork & Aero
Body kits and wings may increase theft appeal. Insurers may request photos to document quality.
Security Upgrades
Thatcham-approved alarms, immobilisers, and trackers are positive factors and may reduce premiums.
Specialist Policy Features
Agreed Value Cover
Instead of market value, you and the insurer agree a value upfront based on photos, invoices, and expert reports. Essential for high-value builds.
Modification Schedule
Good policies explicitly state that listed modifications are covered like-for-like, not just tolerated. Keep itemised records.
Limited Mileage Terms
Enthusiast cars often do low annual mileage—insurers may price accordingly for reduced road exposure.
Track Day Extensions
Normal policies exclude track use. Some specialist insurers offer separate track day cover for circuit sessions.
Specialist Conversions
LPG Conversions
Switching to autogas affects fuel systems and weight distribution. Use certified installers and notify DVLA so the V5C reflects reality.
EV Conversions
Converting classics to electric requires specialist cover. High-voltage safety, battery mounting, and IVA may be required.
Camper Conversions
Van-to-camper builds involve structural changes, gas systems, and electrical installations. Insurers may require gas safety certificates.
Accessibility Adaptations
Hand controls, wheelchair lifts, and swivel seats should all be declared. Many specialist insurers offer tailored terms.
Pitfalls to Avoid
Undeclared Modifications
Failing to declare any change—even cosmetic—can void your policy entirely.
Illegal Parts
DPF removal, illegal tints, and non-E-marked lights won't be covered on road policies.
Undervalued Builds
Standard "market value" policies may undervalue high-cost builds—consider agreed value cover.
Mid-Term Changes
Not informing your insurer after fitting parts means coverage may not match the car at claim time.
Step-by-Step Checklist
Plan Your Build
Decide the scope and research road-legal constraints before purchasing parts.
Notify Your Insurer
Tell your insurer before fitting high-impact parts and confirm ongoing cover.
Document Everything
Keep invoices, photos, alignment reports, and dyno printouts for all work.
Use Quality Parts & Installers
Choose reputable brands and professional installers—torque specs and safety checks matter.
Enhance Security
Add Thatcham-approved alarms, trackers, and secure storage to offset theft risk.
Review Regularly
Update your insurer after each significant change and at every renewal.
Consider Agreed Value
Once the build is complete, agreed value cover protects your investment properly.
Frequently Asked Questions
Do I need to declare small cosmetic changes?
Yes. All modifications must be declared, no matter how minor they seem.
Will every modification increase my premium?
Not necessarily. Security upgrades can help. Performance and theft-appealing changes tend to cost more.
Are remaps always a problem?
Mild, reputable remaps with supporting maintenance may be acceptable to specialist insurers. Extreme gains are red flags.
What about wraps and colour changes?
Wraps should be declared. DVLA doesn't require V5C updates for wraps, but informing your insurer helps with identification.
Can I drive to track days on my road policy?
Road policies cover driving to and from venues, but not track activity. Arrange separate track day cover for circuit sessions.
Is a roll cage road-legal?
Fixed cages can be road-legal but must be properly padded—no sharp edges or exposed mounts. Declare the cage and any harnesses fitted.
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