All this matters because insurers regard modifications with anything from mild concern to deep suspicion. So the golden rule is always to tell your insurance provider if you are planning to modify your vehicle.
Modifying your car could well result in you paying an additional premium – as much as 66% extra, according to our research. But trying to avoid this by not passing on the information is a bad idea – if you fail to inform your insurer you could invalidate your cover completely.
That would cost you dear if you had to make a claim.
The nub of the problem is that any modification, no matter how modest or unobtrusive, alters the original specification of the vehicle.
From an insurer’s viewpoint, that could compromise its safety profile.
Anything that boosts the performance capabilities of your car is particularly sensitive. Fit a turbo-charger, for example, and your insurer will hit you with an upwards premium adjustment at top speed. The simple logic is that enhanced performance increases the likelihood of an accident.
Even purely cosmetic changes, such as a non-standard paint job, might be viewed as risky because it could attract vandals. Fit something expensive inside the vehicle, such as a car phone, and your premium could rise because your car is deemed to be more attractive to smash-and-grab thieves.
When we ran some quotes we found that, as an example, a 30-year-old male who added alloy wheels to his Ford Fiesta could expect to see a 30% increase in his premium. Similarly, if a car phone were added, the cost would increase by 50%.
If the same male motorist ‘pimped up’ his car with a complete body kit, he could expect to see a 66% increase, with annual premiums as high as £900 on average, up from an average of £535.
Pete Harrison, our resident car insurance expert, said: "Cars are used by many of us as a way to express ourselves, and for some people, modifications are an essential part of personalising their vehicle. But motorists need to be aware that even the smallest modification can impact the price of car insurance. It pays to contact your insurer before you go ahead and make any modifications, as you will need to decide whether the extra cost to cover the changes is worth paying.
"Some insurers won't offer insurance to cars that have already been modified, so it's crucial to check with your provider. More importantly, drivers need to realise that not informing an insurer of modifications made to a vehicle can invalidate a policy. This is a mistake motorists can't afford to make."
Our car insurance data shows that the most popular modifications motorists make to their cars include fitting alloy wheels – this accounts for nearly half (43%) of all modifications made.
A further 11% of motorists have opted for tinted windows and 9% have fitted wider wheels or trims to their car. Older drivers – those over 65 – are most likely to add a tow-bar or fit a parking sensor.
Pete Harrison added: "It is a myth that car modifications are only made by so-called boy racers. Many people alter their cars for very practical reasons, such as adding parking sensors or tow bars.
“While some modifications can have a big impact on insurance premiums, others will only have a small impact, or even none at all. And, as ever, different insurers will have different attitudes when it comes to setting their price, so those looking to streamline or tweak their cars should scour the market to ensure they are not paying over the odds.
“On average, motorists save themselves around £400 by shopping around for their insurance premiums through MoneySupermarket.”
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