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  • Writer's pictureSylvain Tornare

Do Modifications Increase the Value of a Vehicle?

Updated: Jan 19, 2022

Modifying a car to make it more personal, sportier or more powerful can be tempting. These modifications are expensive and many people want to recoup some of this investment when reselling the car.

But is this reasonable? Is the value of a modified car really higher?

Carequest Sàrl car broker Switzerland, Nissan GT-R with Liberty Walk body kit

There are different types of modifications, whether mechanical, technological or aesthetic. Some can have a positive impact on the value of the vehicle while others have a negative one. This article provides a guide to understanding the effect of modifications on the resale value of a vehicle.

Types of modifications

Aesthetic modifications

Cosmetic modifications are only intended to make the vehicle more personal or to change its design. Generally, they do not improve performance in any way. In some cases, they may even impair it. This can be the case, for example, when body parts are added or wheels are changed.

Technical modifications

Technical modifications aim to increase the performance of the vehicle. This may involve changes to the engine (parts or programming) or other technical elements such as suspension or brakes. Modifications can be technical and aesthetic at the same time.

Technological modifications

The purpose is to adapt the car to technological developments. This is the case when the infotainment system and stereo are changed or when technologies are added that the car did not have when it left the factory.

Characteristics of the modifications


The quality of modifications can be divided into two categories:

  • Quality of the parts used

  • Quality of the workmanship

Parts from known brands and producers should be favoured. This will reduce the likelihood of issues in terms of reliability and safety. In addition, it will avoid reducing the overall solidity of the vehicle by replacing original parts with parts of lesser construction. It is also important to keep the original parts so that the modifications are reversible.

The assembly must be done by a professional to ensure the correct installation of the elements. In addition, it is important to have a contact person in case of questions or problems.

Vehicle dynamics

Some modifications change the dynamics of the vehicle. In the best case, they improve the dynamics, which compensates for the downsides. Where this is not the case, the value of the vehicle is usually reduced.

If the performance of the vehicle is improved, this does not mean that its value increases. It may be difficult to find someone willing to accept the trade-offs created by modifications regardless of their effect on driving characteristics. For example, shorter suspension springs may improve handling in corners. However, they may hurt comfort. Also, a low car is less practical.

So one should not expect to recoup the money invested in such modifications.


For some people, their car must reflect their personality. Often, personalisation is mainly aesthetic. It can be done with the configuration of a new vehicle or through subsequent modifications. While these changes may be valuable to the current owner, this may not be the case for the majority of potential buyers.

In most cases, the value will therefore be reduced. However, the opposite effect can occur in some cases, especially in the high-end market.

Homologation and inspection

In Switzerland, the homologation rules are strict by international standards. Every modification must be reported to the cantonal traffic office. The vehicle then undergoes an inspection to approve the changes and record them in the vehicle registration document. Homologated components are accompanied by a certificate of homologation, which must be presented at the inspection. If parts are not homologated, the vehicle will not pass the check and will no longer be allowed on the road. It will therefore have to be returned to legal condition before being presented a second time. In addition, the use of these components can lead to penalties in the form of fines or withdrawal of licence.

Unauthorised parts can reduce the value of the vehicle, as not all potential buyers want to take this risk. For this reason, it is essential to keep the original parts.


Therefore, aesthetic and technical modifications do not retain their value. An investment of CHF 20,000 to customise and modify the car will not result in a selling price of CHF 20,000 above the market. In most cases, the modifications reduce the value of the vehicle by limiting the number of potential buyers. To avoid such a situation, it is advisable to take the following points into account before making any modifications:

  • Installation by professionals

  • Use of quality parts from renowned brands

  • Enhancement of vehicle performance rather than customisation

  • Reversibility and availability of original parts

  • Modifications that are homologated and registered

Changes that modernise a vehicle or improve its ergonomics and reliability can, however, increase its value. This is typically the case when adding Bluetooth, a reversing camera or Apple Car Play. Technological improvements are therefore the least likely to hurt the value of a vehicle. However, the above criteria remain valid.

If you have questions about buying a car, do not hesitate to contact us. At Carequest, we make sure that the vehicle you buy measures up to your expectations.


Sources - text

Sources - photos


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