Certain types of vehicle modification are allowed, but approval from the Land Transport Authority (LTA) must be sought. The list includes: 

Engines
The LTA allows swapping of engines between two registered vehicles, provided that both engines are of the same type and capacity. After the swap, one of the vehicles must be scrapped immediately while the other must be produced for inspection at LTA. The following documents are to be submitted for evaluation:

a) Invoice or bill of sales from the supplier of the replacement engine.
b) Certification from vehicle manufacturer or local sole agent stating that the replacement is of the same type as the original one.

Exhaust system
Any modification to the exhaust system, which consists of the exhaust manifold, catalytic converter and muffler, requires the LTA’s approval. These must be submitted to the LTA for evaluation:

a) The certificate from the product manufacturer stating that the proposed aftermarket exhaust system is suitable for the make and model of the vehicle.
b) Test reports from LTA or the National Environment Agency-recognised test laboratories showing that the aftermarket exhaust system complies with prevailing exhaust emission standards.

(Note: Removing catalytic converters and mufflers is not allowed as it will adversely affect the exhaust emission characteristics of the vehicle.)

Seating arrangements
(Adding, removing or rearranging seats)

Modifying the seating arrangements may have safety implications such as overloading and obstruction of access to the gangway. Drawings or sketches of the proposed new arrangement must be sent to the LTA for evaluation before approval is given.

Turbochargers
The addition of turbochargers to a vehicle may adversely affect the safe operation and its exhaust emission characteristics. You need to submit documentation to the LTA before being allowed to make the change.

Some modifications are not allowed at all. These include:

Decorative lamps
(Wiper washer LEDs, undercarriage neon lights, vehicle interior neon lights, etc.)

Installing decorative lamps is not allowed as the lamps may confuse and distract other road users.

Engine capacity
Increasing the engine capacity may lead to premature failure of the engine and other related components. This may also adversely affect the safety and exhaust emission characteristics of the vehicle and therefore not allowed.

Head lamps
(Aftermarket High Intensity Discharge (HID) lamp kits, high wattage bulbs, etc.)

Installation of HID lamp kits is not allowed. Vehicles should only have factory-fitted ones as they have been designed to meet internationally recognised standards. Replacement bulbs of a higher wattage bulb are also prohibited as they may increase the risk of fire because of a greater current being drawn to power these lamps.

This list is not exhaustive. For further advice and clarification on specific modifications, vehicle owners can contact the Vehicle Engineering Department of LTA.

Source: www.onemotoring.com.sg, Singapore’s one-stop motoring portal brought to you by LTA