Customising your car is a great way to make it your own and even improve its performance. However, before you start making any modifications, it’s important to note that there are precautions to take. Many car modifications, both visual and practical, are perfectly legal to make in the UK. But there are also limits on what you can do, and some modifications are not legal or have certain restrictions that you will need to follow. It’s important to know these rules, especially if you’re planning on doing any modifications yourself. When you don’t have professionals to advise you, it’s easy to make mistakes.

Here are some of the important laws you will need to consider if you want to make sure any changes you make to your car are legal and roadworthy.

Licence Plates

Licence plates need to be made so that they can be read with the naked eye, as well as picked up by police technology. If you want to change your plates, you need to make sure you buy new ones from an approved seller. You should make sure that, like Fourdot number plates, the company has a DVLA Supplier Identity Number. This helps to ensure that what you’re buying is legal to use on the road. They should also be a member of the British Number Plate Manufacturers Association (BNMA) and their plates should be made to the current standard (BS AU 145e).

Changes to Lights

Making changes to various lights on your car can be one of the simplest ways to carry out some upgrades. But there are certain changes you can make to lights, and certain changes that are not allowed. For example, neon lights are usually not allowed, although there are some exceptions. One way you can add neon lights is to install them on the bottom of your car, but only if the neon tubing isn’t visible. You also can’t use tints for your headlights or rear lights. Halogen bulbs with a colour temperature over 4,200 K are not allowed, and blue lights are only for emergency vehicles.

Window Tints

Be careful when considering tinting your windows in the UK. Window tinting is allowed, but there are rules as to how much you can tint your windows. Front windscreens have to be at least 75% tint-free and side windows have to be 70% tint-free. There is an exception for some cars, but only those made before April 1st, 1985, which have to have the windscreen and side windows at least 75% tint-free. In addition, it’s not legal to sell a car that doesn’t follow these rules, so it’s not really worth breaking them. Following the rules ensures a safe level of visibility.


Some people are tempted by the sound of a loud exhaust, which they feel allows them to feel the power in their engines. However, loud exhausts can be pretty irritating for other people, so they need to stay within legally allowed limits. An exhaust can’t be above 74 decibels and all cars that are sold are within this limit, in addition to meeting rules for emissions. Making any modifications that increase the level of noise on your exhaust could quickly get you pulled over. Some modifications can also mean that your car is less eco-friendly than it should be.


Changes to spoilers can give cars a sportier look, while also helping to improve handling through better aerodynamics. But before you make any changes, it’s important to know how to modify a spoiler properly. You can make modifications, but you have to use the right method. The spoiler needs to be fastened properly and safely to the car, and it needs to be free of any exposed sharp edges. The spoiler should also be a sensible size that doesn’t get in the way of you having a clear view of the road and your car.


Making changes to your car’s paintwork is a great way to customise it. You can change the colour of your car if you want to give it a respray. Another option is to consider a car wrap, which can allow you to explore a range of designs. However, one thing you have to be careful of is changing your car from the original colour in your V5C logbook. If you decide to do this, you are required to update your details with the DVLA and you should inform your insurer too.

You can modify your car in many different ways, but it’s crucial to check that you’re doing it legally first.