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Modifying your car – do’s and don’ts

Modifying your car – do’s and don’ts

About This Event

Car modifying (car mods) has become big business across the world. This niche market has created a whole subculture of petrol heads from right here in the UK to the other side of the world in Japan.


Mods are all about personal taste. Although there have been trends like getting the car as low to the ground as possible, and some have even spent thousands replacing the entire engine to make their ultimate car.


If you are looking to modify your car in any way, there are a few things you need to consider, especially the legal and safety aspects of certain mods:


In-car entertainment

In car-entertainment is probably the most common mod, even if all you’re doing is swapping the stereo to an aftermarket model. Of course, some drivers like to go all out and install upgraded sub-woofers and speakers.


If you want to keep the passengers entertained, there are TV and DVD systems you can install too. But be mindful it is illegal for these screens to be in view of the driver. So if you wanted to install a visual entertainment system, it’s best to pop it in the back.


Lights and reflectors

By law, the lights on the front of the car must show a substantial amount of white or yellow light, and steady red for the rear. Any other colour is not allowed. It’s illegal to tint any of these lights too as it reduces the amount of light emitted and the effectiveness of the reflectors.


Wheels and tyres

If you fancy giving your motor a new set of shoes, bear in mind new wheels can change the handling of the car. It is advised you only fit wheels and tyres that are approved by the car’s manufacturer. Also make sure there is enough clearance between the wheel and body of the car, especially when steering – you might catch bigger wheels or tyres on the wheel arch when turning.



Upgrading the suspension with stiffer springs, shock absorbers and lowering kits may improve handling, and perhaps you want it to just make the car look great. Suspension mods should only be carried out by a competent mechanic and components should never be cut and welded, as this can weaken the components and can make the car dangerous to drive.



It goes without saying that brakes are the most important safety feature of a car and any upgrades should not be taken with a pinch of salt.


It’s important that they are fitted correctly.


If you’re increasing the braking power of your car, it can be tempting to drive faster into turns, but keep to the speed limit and be wary that this may cause accidents!


Tinted windows

Tinted glass might make driving in bright sunlight a little easier, but when it gets dark, it can be a lot harder to see the road clearly.


There’s no regulations on tinted windows on rear passenger windows or the rear windscreen, but there is a legal limit for the tint on the front windows and windscreen.


The regulations depend on whether the car was used on or after 1st April 1985. The restrictions below are outlined by


Vehicles first used on 1 April 1985 or later

The front windscreen must let at least 75% of light through and the front side windows must let at least 70% of light through.


Vehicles first used before 1 April 1985

The front windscreen and front side windows must both let at least 70% of light through.


Number Plates

Cherished or personalised number plates is a multi-million pound industry in itself! It has become even bigger in the past few years and now people are having to become more inventive to get their perfect plate.


How you display your plate is very important; the characters must be displayed in the correct order, not obscured and not misleading. All the regulations are outlined by


If you ignore and don’t comply with these regulations, you could get a £1000 fine if prosecuted, and the car will automatically fail its MOT.


Once you have changed the plate on your car, you must notify your insurance provider and any applicable aftermarket warranty or GAP/VAP insurance providers.



The spoiler has a pretty essential job on rear-wheel drive cars. It creates down-force on the suspension and helps to stop over-steering.


On sporty front-wheel drive cars like the Ford Fiesta ST, the spoiler is purely cosmetic.


But for whatever reason you fit a spoiler to your car, it shouldn’t have any sharp edges, mustn’t obscure your vision and need to be securely fitted.


Exhaust system

The real benefit for upgrading your exhaust is to give your car that bit of extra horsepower, but a lot of petrol-heads upgrade their exhaust (or add more) for show or for extra noise.


It’s actually is illegal to modify a car’s existing exhaust to make more noise. The police can take action if you’re driving in a way that creates too much noise or you have reduced the effect of the silencer.


Other things to consider

The most important thing to consider if you wish to modify your car, in any way, is the effect it will have on your insurance premium. If you fail to tell your insurer about any modifications, you run the risk of voiding your cover in the event of an accident.


It’s also worth considering any warranty you may have on your vehicle, whether that be manufacturer or aftermarket. Some manufacturers have approved upgrades, such as Mountune for Ford cars that does not affect the warranty. If you’re not sure, contact the administrators of your warranty or a main dealer.

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