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15 Feb 2024

Modified car insurance explained

Find out how modified car insurance works, what counts as a modification and how to get cheaper cover

Dean SobersSenior researcher & writer

In this article

If you modify your car, your insurer needs to know about it ‒ not telling them could invalidate your insurance.

Your insurer may increase your premium, but it may not.

Modified car insurance allows you to modify your vehicle, safe in the knowledge that you (and the modifications) will still be covered. Depending on the insurer, it could cover everything from tinted windows to vehicles adapted for wheelchair access.

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What is modified car insurance?

With modified car insurance, you'll get all the same benefits you would expect from a standard insurance policy. But in addition, the modifications will also be insured.

That additional cover is important for two reasons:

If you need to claim on the policy, you may need repairs to one of the modifications and/or the rest of the vehicle, so you need to be certain your insurer will pay out
Modifications affect a vehicle's value, often increasing it. If you've not paid for insurance that reflects this, you're likely to be under-insured

Find out more: Best car insurance companies in the UK 2024

Does regular car insurance cover modified cars?

Maybe, but maybe not ‒ the only way to know for sure is to speak to your insurer.

In general, insurers point out that even seemingly small modifications can affect a vehicle's value, so it's unreasonable to expect them to price insurance on a standard basis. Insurers also keep detailed data on previous claims by all their drivers; certain modifications may be associated with higher claims rates, so insurers will expect to be given an opportunity to price cover accordingly.

The modifications with the greatest insurance cost tend to be performance-related, such as adding a turbo or supercharger.

You may find some insurers won't offer policies that cover particular modifications, so you may need to go elsewhere. They certainly won't cover illegal modifications.

Key Information

Illegal modifications

Steer clear of making these modifications, or buying a vehicle with them as it won't be considered roadworthy:

Neon lights (unless the tubes are at the bottom of your vehicle and aren't visible or distracting to other drivers)
Tinted headlights and rear lights
More than 25% tinting of your front windscreen (or 30% of side windows)
Exhausts with a noise above 74 decibels
Spoilers that aren't securely fastened or have exposed sharp edges
Nitrous oxide

What counts as a modification?

Anything the insurer says is a modification. If your car is non-standard in any way, you should check with your insurer to see if you need a different type of cover.

People often think of modifications as improving how a vehicle performs, but insurers think more broadly. For example, adding a roof rack might count, so it's important to check.

Common car modifications include:

Bodywork modifications, such as spoilers or body kits
Engine or mechanical modifications that affect performance or reliability. These might include cold air intakes, exhaust systems or ECU modifications
Modifications that change how your car handles, such as uprated brakes or lowered springs
Visual modifications, such as resprays, vinyl wraps, new alloy wheels or tinted windows
Car accessories such as roof racks, tow bars or immobilisers
New or upgraded sound and entertainment systems

Not all of these will increase the cost of your insurance ‒ an immobiliser might bring your premiums down, for example.

Even if you're worried about your premium increasing, don't be tempted to stay quiet about modifications; you might invalidate your insurance if you do.

How can you save money on modified car insurance?

Saving money on modified car insurance requires perseverance. It won't always be possible to get like-for-like quotes from price comparison sites. In any case, there are specialist insurers that aren't listed on these sites. That means doing some ringing around.

Alternatively, an independent insurance broker should know where to find the best deals for your needs.

Another possibility is a policy arranged through a car club or owner's club if you're a member of one.

One option to consider is 'an agreed value' policy, which recognises the time and money spent on a modified vehicle. You agree the value of your car with the insurer and it will pay out this amount if your car has to be written off, regardless of its market value. However, these policies are usually more expensive.

Don't forget the usual ways of cutting the cost of your car insurance. For example, declare your limited mileage if you don't drive the vehicle much, mention any other vehicles you own and any named drivers who may be considered less risky than you. Find more tips for getting cheaper car insurance in our guide.

What is an insurance broker?

Brokers are intermediaries that work with multiple insurers to arrange a policy that suits you. They can save money for their customers by finding far cheaper policies.

Insurance brokers make their money from commission (charged to the insurer) and/or fees (charged to you).

The simplest way to find a broker is to contact the British Insurance Brokers Association by calling 0370 950 1790 or going to biba.org.uk.

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Which insurers offer modified car insurance?

Many high street insurers will insure modified cars as long as you disclose the detail of the changes made.

However, these insurers mainly sell standard policies and are not well set up to deal with more tailored cover. Even if you can get insurance, it may not be the cheapest or the best.

Consider using a smaller insurer that specialises in modified cars. You'll find many advertise their policies online or in the motoring press.

The best option for many people is going to be an independent insurance broker with knowledge of the whole market, including the specialists. They should know where to find the best deals for your vehicle. They may even have relationships with certain insurers so you're offered a lower premium than you would otherwise pay.