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			Environment Protection (Vehicle Emissions) Regulations 2003
 - SECT 21
Penalty for interfering with emission control device
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	21.	Penalty for interfering with emission control device
     A person must not, without just cause-
			(a)	remove or render ineffective any emission control device or emission control equipment which has been installed on or in any motor vehicle by the manufacturer of that vehicle; or
			(b)	interfere with any emission control device or emission control equipment or any component of the engine or exhaust system or fuel system designed by the manufacturer to control emissions so as to render it less effective.
Penalty: 20 penalty units.
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Environment Protection (Vehicle Emissions) Regulations 2003
 - SECT 22
Penalty for interfering with noise reducing equipment
<pre>
	22.	Penalty for interfering with noise reducing equipment
     
		(1)	In this regulation, noise reducing equipment means any absorbing material, shielding panel, device or other equipment of any kind whatever for the purpose of reducing the emission of noise from a motor vehicle.
Note
This includes, but is not restricted to, the exhaust manifold, the exhaust piping, the expansion chamber and the silencer proper.
		(2)	A person who installs, removes, replaces or repairs noise reducing equipment on a motor vehicle must ensure that the vehicle meets the requirements of regulation 10 when the installation, removal, replacement or repair is complete.
		(3)	For the purposes of subregulation (2), a person who installs, removes, replaces or repairs noise reducing equipment on behalf of another person is deemed to complete the installation, removal, replacement or repair on physically transferring the motor vehicle to the person on whose behalf the work was done.
Penalty: 20 penalty units.
			
		
	
 1 Penalty unit is currently ~$122. So ~$2440 fine, or double that if they deem the parts you have removed to also be "noise reducing equipment".
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			16   Motor vehicles emitting excessive air impurities
    An owner of a motor vehicle is guilty of an offence if the vehicle emits excessive air impurities while being used.
    Maximum penalty: 400 penalty units in the case of a corporation, or 200 penalty units in the case of an individual.
			
		
	
 A penalty unit in NSW is currently $110, So (up to) a whopping