SINGAPORE - It's not tough to spot them on the roads. They are the ones with the flashy, colourful lights peeking from the undercarriage on the expressway; they are the ones with the loud, roaring engines that wake up the entire neighbourhood.

Here, in the world's most expensive city to own a car, some car lovers vie to stand out - by zhng-ing, or modifying, their ride. And they do so at great expense: be it money, reputation or even their lives.

In the documentary Zhng: Inside the world of modified cars, CloseUp takes a look at the zhng car subculture that often flies under the radar of the public.

Between 2019 and 2020, the Land Transport Authority (LTA) issued an average of more than 600 notices per month for illegal vehicle modifications. These offences include the installation of non-compliant exhausts, lights and tinted windows.

In a statement to CloseUp, LTA said it takes a serious view of illegal vehicle modifications as these can pose serious safety and environmental hazards.

In May 2021, the owner of car workshop Fong Kim Exhaust Racing Development was charged with replacing the car exhaust systems of two cars with unapproved systems on three occasions.

This is the first time a car workshop here has been charged for carrying out illegal modifications.