Let's take one example: installation of an aftermarket exhaust system. From the onemotoring website:
The exhaust system, which consists of the exhaust manifold, catalytic converter and muffler, is used as part of a vehicle's exhaust emission control system to ensure that the exhaust emission meets our environmental requirements. Any modification to the exhaust system would therefore require LTA's approval. The following should be submitted to LTA for evaluation:
a) Certification from the product manufacturer stating that the proposed aftermarket exhaust system is suitable for the make and model of the vehicle.
b) Certifications or test reports from independent test laboratories such as TUV, DEKRA, JVIA, VCA etc. to show that the aftermarket exhaust system when fitted to the vehicle on a per make and model basis complied with prevailing exhaust emission standards.
After you fulfill the requirements, you pay a fee and submit the vehicle for inspection where a certificate will be issued to state that the vehicle has met all criteria. Hold on to this, I will get back to it.
Here is the infuriating bit.
If the exhaust in question does not possess TUV/DEKRA/JVIA/VCA or independent test lab reports that complies with "prevailing exhaust emissions standards", they will automatically reject your application to have the exhaust installed.
So now this begs the question: why do we need to pay the fee and submit the vehicle for inspection if the local inspection centers are unable to certify if the exhaust system in question can meet the "prevailing exhaust emissions standards"? What are the local inspection centers testing for then? By corollary, why is there a statutory requirement for all vehicles that have been registered for more than 3 years to be subject to these same exhaust emissions tests, with its associated fees?
Even the phrase "prevailing exhaust emissions standards" hints that the person who thought up this policy has no concept of the subject matter.
There are 2 kinds of pollutants: noise and chemical. A catback system by definition is physically located after the catalytic converter(s) and hence does not affect chemical emissions, only noise. So all they need to do really is to set up a mic and record the noise levels at various engine speeds. Simple as that.
And once again here we have double standards. Harley Davidson bikes with noise levels exceeding 100 dBA are allowed on the roads while catback systems at a relatively tame 87 dBA are not allowed. Why? Is it because they didn't have document X...?