6 Things You Need To Know About Insuring A Modified Car

An investigation has revealed some surprising items which insurers may consider modifications - here's what you need to know
6 Things You Need To Know About Insuring A Modified Car

From simple cosmetic changes like a lovely new set of wheels to big jobs like engine changes, there’s a ridiculous amount of choice when it comes to car mods. The world really is your oyster, but there is one sizable hurdle to consider before your start reinventing your ride: insurance.

Hopefully most petrolheads should be aware that something like a hybrid turbocharger or a bodykit needs to be disclosed to insurers, but it’s not as simple as you might think. There are plenty of far less obvious alterations that the company providing your cover will want to know about.

Car Throttle’s sister publication Auto Express teamed up with the British Insurance Brokers’ Association (BIBA) and Ageas insurance to investigate further.

Here’s what was discovered:

Factory-fitted optional extras may count as modifications

6 Things You Need To Know About Insuring A Modified Car

Here’s one that’ll be news to a lot of you - extra stuff that has been added to a car in the configurator may still need to be declared.

This will depend on the company, as there are - annoyingly - two distinct definitions of ‘modifications’ used by insurers. According to BIBA, some claim: “a vehicle is considered modified if it has been changed in any way since it was first supplied by the vehicle manufacturer,” but others go by the line: “any alteration to the manufacturers’ standard specification to your car, including optional extras fitted to the car when new by the vehicle manufacturer or dealer, which improves its value, performance, appearance or attractiveness to thieves.”

If a car has any equipment above its standard spec fitted, your insurer may want to know about it.

Winter tyres shouldn't increase your premium

6 Things You Need To Know About Insuring A Modified Car

One modification that shouldn’t inflate your insurance bill is winter tyres. Something called ‘Winter Tyres – the Motor Insurance Commitment‘ is adhered to by 70 insurers, and it states that winters “do not require an additional premium provided that the tyres meet, and are fitted in accordance with, the relevant manufacturers’ specifications and are in a roadworthy condition whilst in use”. That said, some of these companies may still want to be notified if your car has them fitted.

Many accessories won't affect the premium either

6 Things You Need To Know About Insuring A Modified Car

Winters aren’t the only change you can make without being clobbered by a bigger premium. Many practical accessories like roof racks, tow bars and locking wheel nuts can be added at no extra cost “with most insurers,” BIBA says. Again, though, it’s seen as “prudent” to disclose them to the company that covers you. You’re probably sensing a theme here.

Even stickers and badges should be declared

6 Things You Need To Know About Insuring A Modified Car

Here’s another one that may come as surprise to you - a sticker may not ‘add 5bhp’ as we sometimes hilariously claim, but adhesive additions do count as a modification and thus, they must be declared. One scenario BIBA puts forward is a car adorned with the sticker of a particular sports team, which might make it a target for vandalism from supporters of the arch-rivals.

“Badges indicating increased performance” are also something which insurers deem to raise the risk. Yep, that’s right - slapping an AMG badge on a C180d or an M logo on a 318i can actually bump up the price of your premium.

Owners of modified cars may be better off with a specialist insurer or broker

6 Things You Need To Know About Insuring A Modified Car

Modifications can cost you dearly when buying a policy. Auto Express crunched the numbers to see the difference some typical modifications can make, based on a 1.0-litre Ford Focus ST Line owned by a 37-year-old living in rural Hampshire. The list makes for grim reading.

Partaking in some ECU tuning? That’ll be 18 per cent more, please. How about a turbo upgrade? That’s a whopping 177 per cent increase. A wheel change will see the price rise by nearly five per cent, but bizarrely, ‘performance badging’ accounted for a bigger increase at almost eight per cent. Even aftermarket infotainment systems can nudge the price up, since they make the car more desirable to thieves.

If your car is modified to a particularly committed extent, you may find many firms are unwilling to provide cover at any cost. The answer is to ditch mainstream companies and go for a specialist insurer or broker used to dealing with mods - you might be pleasantly surprised by some of the quotes you get back.

Failure to disclose modifications - however minor - could invalidate your insurance

6 Things You Need To Know About Insuring A Modified Car

There’s a good reason why the general advice is to disclose anything and everything that might be considered a modification - if you don’t, there’s a risk of your policy being voided.

A BIBA case study involving ‘Mr C’ involves an insurer refusing to pay out in the event of a theft. When reporting the theft to the company, Mr C noted several modifications the car had, which he had not disclosed when taking out the policy.

Mr C complained to the Financial Services Authority, which in the end deemed that his non-disclosure was “inadvertent”. Since proper disclosure of the mods would have increased by premium by 75 per cent, the insurer was ordered to pay out part of the claim “to reflect the proportion of the (correct) premium that he had actually paid.”

The case highlights why it’s prudent to err on the side of caution when it comes to insurance and modifications. If you’re in any doubt, speak to the insurer. That being said, it isn’t black and white - BIBA says insurers “recognise not every policyholder is an expert,” so it’s up to customers to supply information that’s “best of their knowledge and belief.”



Dealing with insurance can be a pain. A few months ago i was hit by another driver who had modified their car and not informed their insurance company. As soon as his insurance company realised there was no way to blame the crash on me. They tried to void his insurance which meant they would not of been liable to pay out for damages to me and my vehicle. Luckily they did not manage to do this. But its a cautionary note that when your insurance gets voided it does not just effect you it can effect other people as well and can then make you liable for the damages.

09/25/2019 - 15:34 |
34 | 0
Charlie gibbons


09/25/2019 - 15:34 |
2 | 0

I love knowing that fake badgetards have higher premiums

09/25/2019 - 15:58 |
24 | 0

You think someone who puts an M badge on a 318i will have told their insurance?!

09/25/2019 - 16:02 |
18 | 0

Riddle me this. I was involved in a crash in my modified citroen years ago, it had all sorts of modifications, obviously not factory wheels, OEM replaced front bumper, resprayed badges, exhaust, induction, remamp and the list goes on. The car was a write off and they gave me £2500 for it. I was with Direct Line insurance. Was I just lucky?

09/25/2019 - 16:10 |
6 | 0
Miki Jowett

In reply to by Anonymous (not verified)

Depends on the insurer and their wording. They would’ve been within their rights to void the policy ab initio if they felt you’d not made a fair presentation of the risk by not declaring mods. However, if the proximate cause of the accident wasn’t the mods, they may have taken a more lenient stance. Without declaring mods however, the best case scenario should in theory be the market value of the car, less modifications. This is why if you’re putting serious money into a project car you want to declare mods and get an agreed valuation policy. Otherwise you could be left seriously out of pocket!!

09/25/2019 - 16:29 |
4 | 0

Phils looking very pleased with himself, a feel a video update coming on

09/25/2019 - 17:45 |
0 | 0

For the french guys here: just DON’T tell your insurance anything, or it will just be voided. Thats all

09/25/2019 - 20:30 |
26 | 0

Yep, no project mx-5 can happen here.

09/25/2019 - 22:44 |
0 | 0

Pretty much the rule in the UK too if you are 17-25. Fortunately most body repairers don’t note minor modifications to insurers.

09/27/2019 - 15:50 |
2 | 0

yeah losing your car is always a bad PHILing

09/25/2019 - 21:33 |
4 | 6

Sorry insurers, but you’re wrong. A factory-fitted optional extra is not a modification. Its factory.

09/25/2019 - 22:41 |
4 | 0

In reply to by Anonymous (not verified)

I had to declare the prodrive package on my impreza, that was a factory fitting, but classed as a modification

09/26/2019 - 06:28 |
2 | 0
Robert Gracie

I know someone who secretly tried to modify their car engine without declaring it to the insurance company but the insurance company that he was with found out and they booted him off his insurance because he added a turbocharger to the car and he didnt declare it and he lost his insurance for good and hes now got insurance with a different company and well hes learned his lesson considering his insurance is crazy now because of the amount of body work modifications he did just to make his Fiat Punto look cleaner because of it, you touch the engine and you are booted from the insurance, silly idiot…

09/26/2019 - 07:54 |
0 | 0
Danny S

Shannons in Australia is mint for insurance. I got a quote for an engine + 5 speed swapped 1960’s Toyota Corona (which I was considering, but didn’t end up buying). Literally no higher premium than the standard car (which is already cheap to insure with full coverage), even though it probably had 50% more power than stock, and I’m a young driver.
Side note, I find it amusing when I hear people in Australia complaining about how restrictive mod laws are here (they’re bad at all); when I know how much trouble y’all in Europe have modifying cars legally and insuring them.

09/26/2019 - 13:35 |
0 | 0


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