A guide to car mods and insurance: which do you need to tell your insurer about? This informative guide is designed to keep you on the right side of the law.
Modifying Your Car? Here’s What You Need to Know
Upgraded wheels, tinted windows, a remap for extra power—it’s easy to get caught up in improving your car. But if you don’t tell your insurer, those modifications could leave you uninsured when you need cover.
Not all mods increase your premium—some, like security upgrades, might even reduce it. But failing to declare modifications could mean:
- Your insurer cancels your policy.
- A claim is rejected after an accident.
- You face penalties for driving with undeclared changes.
Let’s break down what car mods you need to disclose and what happens if you don’t.
Which Modifications Must You Declare?
The simple rule: If it changes your car from its factory specification, your insurer needs to know.
| Type of Modification | Examples |
|---|---|
| Performance Enhancements | Turbochargers, remaps, aftermarket exhausts, cold air intakes. |
| Cosmetic Changes | Body kits, custom paint, vinyl wraps, tinted windows. |
| Wheels & Suspension | Lowering kits, coilovers, aftermarket alloys, spacers. |
| Interior Mods | Racing seats, roll cages, steering wheel swaps, upgraded infotainment. |
| Security Upgrades | Tracker systems, immobilisers, additional alarms. |
| Other Mods | Tow bars, LPG conversions, engine swaps, or any non-standard additions. |
Some insurers may be fine with minor modifications—but if they aren’t disclosed, they can refuse to pay out in an accident.
Performance Mods: The Biggest Risk
Anything that increases speed or power output is a red flag for insurers. Remaps, turbochargers, or even an upgraded exhaust system can increase accident risk, leading to a higher premium.
What happens if you don’t declare it?
Insurers will check for undeclared modifications in the event of a serious crash. If they find changes you didn’t disclose, your claim could be rejected entirely—even if the modification wasn’t relevant to the accident.
What Happens If You Don’t Declare Modifications?
1️⃣ You Get Pulled Over & Fined
Certain mods—like illegal tints—can lead to police fines, penalty points, and MOT failures. You could be stopped and penalised if your front windows are too dark.
2️⃣ Your Policy Gets Cancelled
Undeclared modifications can lead to your insurer cancelling your cover, leaving you uninsured and illegally on the road.
📷 Pictured: A Golf R on a driveway, with a letter reading “COVER CANCELLED” next to a damaged car.
3️⃣ Your Claim Gets Rejected
Imagine you’re in an accident, and your insurer finds an undeclared remap or suspension mod. They refuse to pay out, leaving you to cover all costs.
Does Declaring Mods Always Increase Insurance?
Not necessarily. While performance mods typically increase premiums, some modifications can lower them:
✔ Security upgrades (trackers, immobilisers)
✔ Dash cams (some insurers offer discounts)
✔ Parking sensors (reduced accident risk)
The key is being upfront—some insurers specialise in modified cars and can offer better rates than mainstream providers.
Selling a Modified Car?
Are you thinking of selling your modified car? Some dealerships won’t take them, but others appreciate high-quality upgrades from trusted tuners like Litchfield, Overfinch, and Urban.
At webuysupercars.com, we specialise in performance and prestige cars, even some mildly modified ones. If you’re struggling to find a buyer, get in touch
Final Thought: Don’t risk it.
Declaring modifications isn’t just about avoiding penalties—it’s about ensuring you’re covered when it matters most.
✔ Upgraded your car? Tell your insurer.
✔ Thinking of selling? Know your options.
How car modifications affect your insurance – Aviva