Sometimes, modifying a car can feel like you’re entering a minefield. First, you’ve got to decide which parts you’d like. Then, you’ve got to find the right parts to fit your specific car. Next, you’ve got to make sure they’re installed correctly - and to top it all off, you’ve got to make sure your car is legal and still passes its MOT. There’s a lot to think about.

Part of ensuring your car is legal is, unfortunately, declaring modifications to your insurance company. We say ‘unfortunately’ because declaring modifications is likely to push your premium up - an extra cost you could do without.

Still, it’s better to declare modifications and pay a little extra to your insurance company than to risk not declaring them at all. Technically, if you don’t declare modifications, you’re driving without insurance. Plus, should you get into an accident and your insurer realises your supposedly standard car makes twice the horsepower it originally did, they won’t pay out. 

It’s simply not worth taking the risk. So, to help make life a little easier, we’re going to run through which modifications are likely to affect your premiums and which aren’t. Later, we’ll also talk about specialist insurance for modified cars and determine whether it’s worth looking into.  

Which mods will I need to declare?

We hate to break it to you, but… basically all of them. No matter which insurance company you go with, you’ll have to declare all of the mods you’ve done to your car to make sure they’re covered. Even minor add-ons like window tints and stickers need to be declared - not just upgrades that affect performance. Here’s an overview of the kind of mods insurers will want to know about.

• Engine upgrades like induction kits, ECU remaps and aftermarket turbochargers
• Aftermarket exhausts, including manifolds, cat-back systems and everything in between
• Suspension and chassis-related mods, from coilovers and air ride to adjustable arms, strut braces and uprated anti-roll bars
• Brake upgrades, including discs, pads and callipers
• Non-standard wheels and tyres, even if they’re the same size as the originals
• Any changes to the bodywork, such as aerodynamic add-ons, aftermarket headlights and taillights, carbon door mirrors and so on
• Non-standard paintwork (in a different colour to the original), stickers, decals and window tints
• In-car upgrades like seats, steering wheels, pedals, sound systems and roll cages

If your mods don’t fit into any of the categories above, don’t assume that you don’t have to declare them. If you’re in doubt, always tell your insurer - it’s better to be safe than sorry. A general rule of thumb to follow is this: if a part didn’t come fitted to your car as standard (and wasn’t available as an optional extra from new) you should tell your insurance company about it.

What modifications affect car insurance prices?

Most aftermarket performance upgrades are likely to push your premium up, although there are exceptions - and these price increases will vary significantly depending on which insurer you choose.

Some insurance companies simply won’t insure modified cars at all, or will quote you an astronomical price. Others, by contrast, specialise in insuring modified cars and understand the risks much more clearly, allowing them to cover a vast array of different modifications without charging you a fortune. So, the only way to get an accurate picture of how much each modification will alter your premium is to call up your insurer and ask. We would always recommend speaking to two or three different insurers to make sure you’re not paying over the odds.

Although it’s impossible to tell you exactly what effect different mods will have on your premium, there are some statistics out there that can give you a rough idea of what to expect. According to specialist insurer Keith Michaels, for instance, exhaust system changes typically tend to inflate premiums by 26%. Air filters can push premiums up by 25%, while more significant mods like aftermarket turbo kits can push your insurance bill up by a whopping 132%.

These percentages only apply to standard insurers, though. If you speak to a specialist modified car insurer, you can expect these increases to be much more manageable (more on specialist insurers in a moment).

Are there any mods that will bring my insurance down?

We know there’s been a lot of bad news so far in terms of prices, but declaring mods won’t always push your premium up - there are some aftermarket add-ons that can actually make your insurance cheaper…

• Security upgrades like upgraded alarm systems, immobilisers, tracking devices and steering wheel locks
• Aftermarket safety devices like parking sensors
• Dash cams

Is there specialist insurance for modified cars?

Yes! As we’ve previously mentioned, specialist modified car insurers are almost certainly the way to go - especially if you plan on significantly upgrading your car. 

If you’re only adding small bolt-on parts like an air filter and an exhaust, sticking with a mainstream insurer may prove to be cheaper. But if you plan on making serious changes to the way your car looks and performs, we would strongly advise speaking to an insurer who knows and understands modified cars.

Not only will specialist insurers probably give you a cheaper quote, they’ll better understand the value of your modifications and are more likely to pay out their full value should you be involved in an accident or have your car stolen. Let’s not forget that modifications can be worth a lot of money in themselves - you want to make sure they’re covered should the worst happen.

Shop for mods and styling parts at LK Performance Today

We hope our guide has helped demystify the relationship between mods and insurance once and for all. If you’re still planning your build or want to start getting parts for your car, we can help with that too. Here at LK Performance, it’s what we specialise in!

As one of the UK’s leading suppliers of performance car parts, we stock everything you need to make your car one-of-a-kind. From show-stopping wheels to track-ready coilover kits and tuning parts from all your favourite brands, we have thousands of incredible parts on the shelf. To get started, check out our complete range of wheels, tyres and performance parts online today.