The study, which compared car insurance prices across the market, discovered that quotes for motors with modifications were an average of 139% higher than those without. In the most extreme case, a 20 year old male with no claims or convictions to his name, driving a VW Golf 1.5l, would be expected to pay almost three times more for his car insurance if he chose to add modifications.

Popular car modifications include tinted windows, lower suspensions, spoilers and alloy wheels and Confused.com has warned that such add-ons can not only raise the cost of insurance but also render insurance invalid if the owner fails to disclose details of changes to the insurer.

“It also needs to be considered that adding modifications to your vehicle can greatly depreciate its value when selling it on. If drivers must modify their cars, we urge our customers to shop around before committing to one insurer,” said Will Thomas of Confused.com.