When it comes to modifying your car, there are plenty of options. The car modification industry is growing rapidly, substantially boosting the economy. Add to that, it can seriously enhance the power and the driving experience, so it’s no wonder car mods are increasingly popular. However, there are a few things you need to be aware of before pimping your ride; namely, car modification laws.



Exhausts are one of the more popular mods, with plenty of petrolheads updating their exhaust systems. However, be aware of the car exhaust laws before you go ahead. Big-bore exhausts are not legal on UK roads due to the excessive noise and emissions, particularly as the UK government are clamping down on the CO2 emissions.

Most brand-new exhaust systems are effective at increasing the engine performance, but just remember those car exhaust laws. If you do want to go loud but live in an urban area, we recommend putting exhaust silencers in place if you do upgrade your exhaust.

Engine tuning

Engine tuning boxes and car remapping are completely legal, but remapping can void your warranty. Engine tuning boxes, on the other hand, are a temporary aftermarket mod and, therefore, can be removed without trace should you return the car or even sell on. If you are permanently remapping your car, it is suggested that you inform the insurer. If you were to have an accident and they were not informed, it could see your insurance claim void.


Car modification laws also relate to any brake upgrades. Larger brake callipers and vented brake discs are common aftermarket mods, but it’s recommended you seek professional advice. Poor brake mods could not only be costly to repair but, potentially, place you in dangerous situations. Alternatively, you could see the advice of the car manufacturer or supplier.

Undercar lights

Undercar lights are, certainly, one of the biggest fads in aftermarket mods. The right undercar lighting can seriously improve the look of a vehicle but, if not properly installed, you are failing to comply with UK car modification laws. It’s important that the tubing does not show and the lights must not be too bright as to distract other drivers. You should also add an on/off switch for the undercar lights.

Other lights

If you do modify your head lamps or fog lights, they must be white/yellow at the front and can be no other colour. Likewise, the lights should be red at the rear. Blue lights are strictly prohibited for anyone who likes the colour…

Tinted windows

There’s no denying that tinted windows look good, but you need to know the UK car modifications rules and regulations before upgrading your windows. The windscreen and front side windows can be tinted, but they must allow for light transmissions of 75% and 70%. If your car doesn’t meet those regulations, you could be served with a Prohibition Notice and a hefty fine to boot.


Spoilers can look smart and even improve handling, but huge spoilers can be an obstruction according to UK laws. Any spoiler must be properly fitted to the car and not obstruct your view. If it does, you might be asked to remove the spoiler. However, it is a relatively easy car mod and can massively change the appearance of your car, from as little as £100.

If you want to discuss engine tuning and the best box for your car, you can get in touch with our team. Alternatively, select your model and the right car tuning box.