Performance modifications hit UK drivers hardest in the wallet 

Drivers face the steepest insurance increases when making performance-related modifications to their cars.  

Chipped or remapped engines, aftermarket suspension and exhaust system changes lead to the biggest premium increases – at an average of 15.9% each across all 10 UK cities in the study.  

These performance upgrades are a signal to insurers that drivers may be more likely to drive aggressively or take risks, resulting in higher premiums. 

Sam Sheehan, motoring editor at cinch, commented, “It’s always worth getting an updated insurance quote before modifying your car. You don’t want to be surprised by an increase of a couple of hundred pounds for what feels like a small modification. 

“You must inform your insurance company about any modifications you make. If you don’t, your insurance will no longer be valid.” 

Surprising modifications that still cost extra 

Even seemingly minor modifications can impact insurance costs. Tinted windows and rear spoilers both increase premiums by 12.10% on average.  

More surprisingly, upgraded brakes increase insurance at the same rate as cosmetic changes such as non-standard resprays and side skirts, all going up by 4.52% on average.  

Sheehan explained, “The insurance increases for these modifications might come as more of a surprise. Something as simple as tinted windows can add over 12% to your annual premium, and a safety upgrade can make your insurance go up too.” 

Modifications that won’t break the bank 

Not all modifications will hike up your insurance quote. cinch’s research found three modifications which each resulted in a modest 0.79% increase on premiums: alloy wheels, wheel trims and driving lights. 

These modifications are generally viewed by insurers as low-risk cosmetic changes that don’t affect performance or safety. 

London tops the list for expensive modifications 

You may be surprised to learn that where you live affects your insurance premiums. 

Insurers use dozens of indicators to generate quotes for drivers. Historical location-specific data on car crime levels and traffic incidents will be taken into consideration, along with other factors like average salary. 

The top 10 UK cities for increases to insurance premiums following a car modification(s) are: 

When it comes to location, London drivers face the highest average insurance increases for car modifications at 8.88%. Liverpool follows closely at 8.72%, with Leeds taking the third spot at 8.53%. Belfast and Bristol drivers get the best deal of the cities surveyed, with average modification-related insurance increases of just 7.01% and 7.00% respectively. 

“Location plays a big part in how much modifications affect insurance,” said Sheehan.  

“Whether it’s a higher-than-average car crime rate or the simple fact that there is more wealth concentrated in London, drivers in the capital might want to think twice before modifying their car.” 

Expert advice for modification-minded drivers 

Sheehan advises, “Before making any modifications, drivers should speak to their insurer about potential cost increases. 

“What seems like a harmless upgrade could result in a costly surprise when renewal time comes around. The key is to factor insurance costs into your modification budget from the start.” 

The research highlights the importance of understanding the full financial impact of vehicle modifications beyond the initial installation cost, with insurance premium increases potentially adding hundreds of pounds to UK drivers’ annual motoring expenses. 

Whether you’re driving a brand-new model or a used Ford, it’s important to take these hidden costs into consideration when planning any upgrades.