Car modifications trigger insurance premium hikes

  • Male motorists are most likely to install turbo engines, while female drivers opt for parking sensors
  • Not informing insurer of car modification could mean policy is VOID

Modifying your car could double your insurance premiums, new insight from MoneySuperMarket reveals. Analysis of 2.3 million insurance quotes for modified vehicles found that adding performance-enhancing and aesthetic features increase premiums the most and may invalidate an insurance policy if the insurer isn’t informed.

Fitting a turbo engine could boost premiums by up to 132 per cent – the average premium rising from £494 to £1,1461, more than double – and drivers may see their premiums inflate by up to 66 per cent if they change their car’s bodywork by adding a bonnet bulge, flared wings or wheel arches.  Other modifications that cause significant hikes include:

  • Transmission or gearing changes (63 per cent rise)
  • A complete body kit and panel (57 per cent)
  • Roll bars, roll cages and the removal of seats (41 per cent)
  •  ‘Uprated’ brakes (36 per cent)
  • Changes to the exhaust system (26 per cent)
  • Upgrading the suspension (25 per cent)

Drivers looking to change the physical appearance of their car by having paintwork done or adding ‘stripes, decals or badges’ will see premiums rise by up to 36 per cent and 22 per cent respectively. On the other hand, some modifications tend to push premiums down. Adding parking sensors will see average prices fall by 13 per cent and installing a tow bar – typically meaning slower driving – will see premiums reduced by 20 per cent on average.

According to MoneySuperMarket analysis, the most popular car modifications are as follows:

  1. Adding alloy wheels
  2. Installing a tow bar
  3. Having suspension work done
  4. Making changes to the exhaust system
  5. Adding tinted windows

Kevin Pratt, consumer affairs expert at MoneySuperMarket, said: “Modifications can be a great way to personalise a car and in some instances will improve performance, but can quickly bump up the cost of your car insurance. Insurance is based on risk, and modifying your car is a warning sign to insurers.

“For example, spoilers or turbo engines will mean a vehicle goes faster, and therefore increase the likelihood of an accident, while car phones and sat-navs are attractive to opportunistic thieves, so insurers balance the scales by pushing premiums up.”

“Pimp my ride”

Female drivers are more likely to opt for functionality improvements, while male drivers are fonder of aesthetic and performance-enhancing modifications. Men are six times more likely to install a turbo engine, or add ‘uprated’ brakes. Women on the other hand, are 44 per cent more inclined to choose parking sensors.

Kevin Pratt continued: “For some, modifications are an addictive hobby, but the most important thing to remember is to inform your insurer of any changes, preferably before you make them, so you can find out the impact on your insurance. You certainly shouldn’t wait until it’s time to renew your policy.

“When you change anything about your car, you change the original specification which may invalidate your policy if you don’t inform your insurer. Reporting the changes might mean a higher premium, but having an invalid policy is considered fraudulent and could reduce or even remove the prospect of a pay-out if you had to make a claim.

“At a time when premiums are high and getting higher, drivers should be doing everything they can to get the best possible price. Those who have modified their vehicles and experienced price hikes should shop around at renewal to ensure they’re getting the best deal possible. Using MoneySuperMarket could save 51% of customers up to £231.74 on their car insurance.”

Find out more about car modifications and the impact on car insurance at


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