Tuning companies warned over illegal car modifications

Court puts burden on tuners to satisfy themselves that the cars won't be used on public roads

Tuning companies warned over illegal car modifications
Image: Bigstock.

A Slough-based tuning company has been fined £5,800 for fitting an unsuitable part to a vehicle which would make it illegal to be used on the road.

It’s the second time a performance tuning company has been charged by the Driver and Vehicle Standards Agency (DVSA). In November 2023, a similar case was brought against Wakefield-based AET Motorsport for fitting a ‘pop and bang’ exhaust system to a Ford Fiesta ST.

An investigation by the DVSA’s Vehicle Market Surveillance Unit found that Onyx Performance failed to establish whether a vehicle would be used on the road following the removal of the catalytic converter and exhaust silencer.

The Vehicle Market Surveillance Unit makes sure vehicles, vehicle parts and vehicle accessories sold in the UK are safe for people to buy. Anyone can contact the unit to report a vehicle manufacturer, supplier, dealer or private seller if they believe they’re breaking the law.

Reading Magistrates’ Court ruled that the burden is on car modification companies to satisfy themselves that cars are not being used on public roads. Crucially, they should ask the customer how they intend to remove the car from their premises.

Roads Minister Guy Opperman said: “It’s great to see DVSA cracking down on this anti-social and dangerous behaviour and successfully prosecuting companies who breach the rules.

“Everyone knows that horrific sound, when exhausts go “pop and bang” in the street, and cracking down on companies that fit these modifications shows our commitment to ensuring Britain’s roads remain among the safest in the world.”

Chris Dormand, DVSA’s head of the Market Surveillance Unit, added: “We’re delighted with this outcome which, combined with a recent similar prosecution, highlights that companies must act within the law.

“Companies must satisfy themselves they are certain that vehicles which have had modifications designed for off-road use are not used on public roads. Modifications designed for off-road use are illegal on our roads and businesses will be held accountable.

“It is illegal to drive a vehicle on the road after the exhaust system has been altered to increase noise levels or adversely affect emissions. They are anti-social, unhealthy and result in an MOT failure. DVSA takes this activity seriously and where appropriate, we will prosecute companies who offer similar services.”

Onyx Performance was ordered to pay a total of £5,800 in fines, victim surcharge and costs for fitting an unsuitable vehicle part to a vehicle which would make it illegal to be used on the road.


  1. Good I despise / detest those pop pop bang exhausts

    • Yes the people who drive these cars are total cretins. I wish the police would actually pull more people over when they hear a car like this

      • Would be nice if the MOT testers issuing tickets to said cars are also removed from the system. If testers did the job these vehicles would soon be put back to stock

        • Sorry but In defence of these mot testers testing these vehicles. Other than extreme cases, A lot of these vehicles will not pop and bang or behave any different under normal driving conditions and Performing an aggressively driven road test or revving the guts out of these said vehicles to try and make it pop and bang, is NOT part of the current mot test !! Some of these pop & bang maps can be carried out on a vehicle with a totally standard exhaust system too, so unless the exhaust system is obviously modified for off road use, defective, emissions regulation components removed, it’s excessively noisy or it doesn’t pass a emission test, then it’s the vehicle’s owner that wants removing from the system not the mot tester just carrying out his job.!! Many thanks.!!

  2. That’s the end of the WRC then!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

The reCAPTCHA verification period has expired. Please reload the page.

Have your say!

3 1

Lost Password

Please enter your username or email address. You will receive a link to create a new password via email.