Cars
Modified car insurance: how to tell if a policy really covers your mods
The best insurance for modified cars is the policy whose wording fits your mods. Check parts cover limits, repairers, track day exclusions and mileage.
The best insurance for modified cars is the policy whose wording properly covers the changes you have made, at a value and on terms that match how you use the car. Two policies at a similar price can pay out very differently after a theft or accident, so the detail in the policy wording matters more than the headline premium.
This guide explains what counts as a modification, what the law expects you to declare, and a checklist of the policy terms to compare before you buy.
What counts as a modification for car insurance?
The Financial Ombudsman Service describes a modification as any change to your car that is not part of the manufacturer's standard specification. That runs from alloy wheels and tinted windows through to exhaust upgrades, engine tuning and ECU remapping.
Insurers draw the line in different places. Which? points out that even a roof rack can count, so the working rule is that anything your insurer calls a modification needs declaring. It also makes no difference who fitted the part. If you bought the car with mods already on it, they are part of the car you are insuring.
Some changes go beyond insurance. GOV.UK says you must update your V5C if you change the colour, engine, cylinder capacity, fuel type (for example converting to electric) or seating capacity. Bigger structural work, such as removing the roof or altering the chassis or bodyshell, has to be reported to DVLA on a modified vehicle statement. Keeping the logbook and the insurance declaration consistent avoids awkward questions at claim time.
Car insurance for modified cars: what does the law expect you to declare?
For private (consumer) car insurance, the key law is the Consumer Insurance (Disclosure and Representations) Act 2012. It says it is "the duty of the consumer to take reasonable care not to make a misrepresentation to the insurer." In practice that means answering the questions you are asked honestly and carefully, including the question about modifications.
If an insurer later finds an undeclared modification, what happens depends on why it was missed. Under Schedule 1 of the Act:
| Type of mistake | What the insurer can do |
|---|---|
| Deliberate or reckless | Treat the policy as if it never existed, refuse all claims and usually keep the premium |
| Careless, and the insurer would not have offered cover at all | Cancel the policy from the start and refuse claims, but refund the premium |
| Careless, and the insurer would have used different terms | Treat the policy as if those terms applied (for example an exclusion) |
| Careless, and the insurer would have charged more | Pay only a proportion of the claim |
The Ombudsman's modifications guidance shows how this plays out. In its published examples, a policy was voided where the driver had not declared modifications they were asked about, and another where the driver knew about an undeclared engine remap and exhaust changes, while policies were reinstated where oversized alloys were not something an average person would have noticed, and where an air filter change had a negligible effect on performance. The Ombudsman also says it is unlikely to side with you if you left out a significant modification that the policy clearly asked about.
The third party cover that is the legal minimum on GOV.UK applies to modified cars too, so this is about keeping valid cover, not just protecting your own car.
What to check in a modified car insurance policy before you buy
The pages that tell you to "go to a specialist" rarely say what to look for once you get there. These are the clauses worth reading line by line, and the questions to put to whoever arranges the cover.
1. The limit on modification and parts cover
Policies differ in how they treat aftermarket parts, so read the modifications section closely. Check whether there is a single limit for all modifications, a limit per item, and whether labour to fit them is included. If the value of your parts is higher than the policy's modification limit, the difference may not be paid after a total loss.
2. Like for like, genuine or standard replacement parts
Read how the insurer replaces damaged parts. "Like for like" may mean a part of similar type and quality, "genuine" usually means the original brand, and some wording allows the car to be returned to standard specification. If your exhaust, wheels or body kit are specific brands, check which of these applies.
3. Valuation: market value or agreed value
On a write-off, a market value policy pays what a similar car would sell for, which may not reflect money spent on modifications. An agreed value policy fixes the figure in advance; Which? describes it as an option that recognises the time and money spent on a modified vehicle. Our guide to agreed value vs market value after a write-off goes through this in detail.
4. Choice of repairer
Check whether you must use the insurer's approved repairer, or whether you can choose a specialist who knows your car. If you can use your own, check whether the policy caps what it will pay towards the bill.
5. Track days, shows and events
Read the exclusions for track days, sprints, timed events and anything on a closed circuit. Also check whether the car is covered while on display at a show, and while being driven to and from one.
6. Mileage limits and use
For weekend or show cars, Which? mentions declaring low mileage as a way to keep costs down. Check what happens if you go over the limit, how mileage is recorded, and whether the class of use (social only, commuting, business) fits how you drive.
7. Adding modifications mid-term
Look at the conditions on changes during the policy. Find out how you tell the insurer about a new part, whether there is an admin fee, and whether cover for that part starts straight away. The Ombudsman's advice is to check your policy before modifying and to tell your insurer as soon as possible.
8. Security conditions and excess
A policy for a modified car may include conditions such as a tracker, an approved immobiliser or garaging overnight. Breaking a security condition can affect a theft claim, so check that each one is realistic for you. Also note whether there is an extra excess for theft or for young drivers.
Modified car insurance comparison: comparing cover, not just price
A useful modified car insurance comparison puts the policy wording side by side. A simple way to do it:
- List every modification with its value and, where possible, receipts and photos.
- Give the same list to each insurer or broker so the quotes are for the same risk.
- Ask for the full policy wording, not just the price.
- Compare the eight points above for each quote.
- Check the total excess, and any extra excess for theft or named drivers.
- Before you pay, confirm in writing that each modification is listed on the schedule.
Which? suggests looking at smaller insurers that specialise in modified cars, an independent broker with knowledge of the whole market, or a scheme arranged through an owners' club. If you would like a specialist broker to look at your car, you can get modified car insurance quotes: you fill in a short form and a specialist broker from the panel contacts you with quotes. There is more on what these policies include in car insurance for modified cars: what a specialist policy covers.
What affects the price of modified car insurance?
The price depends on how each insurer sees the risk, so there is no single answer. Modifications do not always raise the premium. According to Which?, performance changes such as adding a turbo or supercharger tend to have the most effect, while some security upgrades, such as an immobiliser, may lower it. The Ombudsman adds that insurers may argue that an undeclared modification put the car at a higher risk of being stolen.
The usual factors still apply too: the driver's age and record, where the car is kept, the mileage and the excess you choose. Some modifications can make a car unroadworthy, and Which? lists nitrous oxide and tinted headlights and rear lights as examples.
Modified car insurance reviews and companies: how to check who you are dealing with
Reviews can tell you how a firm handles calls and claims, but they cannot tell you whether a policy suits your car. For modified car insurance companies, the more reliable checks are:
- Look the firm up on the FCA's Financial Services Register, a public record of authorised firms that also helps you spot clone firms.
- Ask whether they arrange cover with insurers that accept your specific modifications.
- Read how complaints are handled. If a firm does not resolve a complaint, you can usually take it to the Financial Ombudsman Service.
If your car is a Japanese import as well as modified, the import side brings its own terms to check, covered in best insurance for Japanese imports.