[Zedn]

I found the where it fits into the law.

Its under the protection of environmental operations (clean air) reg 2002.

15 Use of motor vehicle without prescribed anti-pollution device prohibited

(1) An owner of a motor vehicle who uses the motor vehicle, or causes or allows it to be used, is guilty of an offence if:
(a) this Regulation requires motor vehicles of the class to which it belongs to be fitted with a prescribed anti-pollution device, and
(b) the vehicle is not fitted in the prescribed manner with such a device.

Maximum penalty: 400 penalty units in the case of a corporation, or 200 penalty units in the case of an individual.

17 Removal or adjustment of anti-pollution devices

(1) The owner of a motor vehicle who uses the motor vehicle, or causes or allows it to be used, is guilty of an offence if:
(a) an anti-pollution device had been fitted to the motor vehicle, and
(b) at the time of that use the device had been:
(i) removed, disconnected or impaired, or
(ii) adjusted or modified and the adjustment or modification results in the emission of excessive air impurities by the motor vehicle.

Maximum penalty: 400 penalty units in the case of a corporation, or 200 penalty units in the case of an individual.

Thats a maximum of $22000 for an idividual.

And for the noise it comes under POEO (noise control) reg 2008

12 Use of motor vehicles on road or road related area

(1) A person must not cause or permit a motor vehicle to be used on a road or road related area if the motor vehicle is capable of emitting noise at a level in excess of the level prescribed by clause 4 (b) or (c) for that type of motor vehicle (the prescribed noise level).

Maximum penalty:

(a) if the vehicle is capable of emitting noise at a level that exceeds the prescribed noise level for that type of motor vehicle but does not exceed that prescribed noise level by 5 dB(A)—100 penalty units in the case of a corporation, 50 penalty units in the case of an individual, or
(b) if the vehicle is capable of emitting noise at a level that exceeds the prescribed noise level for that type of motor vehicle by 5 dB(A) but does not exceed that prescribed noise level by 15 dB(A)—150 penalty units in the case of a corporation, 75 penalty units in the case of an individual, or
(c) if the vehicle is capable of emitting noise at a level that exceeds the prescribed noise level for that type of motor vehicle by 15 dB(A) or more—300 penalty units in the case of a corporation, 150 penalty units in the case of an individual.

this is 4 (b) or (c) that it refers to

(b) the prescribed level for a motor vehicle of a particular type that is certified to ADR 83/00 is:
(i) if the compliance plate date of the vehicle is on or before the date that is 2 years after the commencement of this Regulation—the noise level established by ADR 83/00 for a motor vehicle of that type when stationary plus 5 dB(A) or the noise level specified in Schedule 1 for a motor vehicle of that type, whichever is the greater, and
(ii) in any other case—the noise level established by ADR 83/00 for a motor vehicle of that type when stationary plus 5 dB(A), and
(c) the prescribed level for a motor vehicle of a particular type that is not certified to ADR 83/00 is the noise level specified in Schedule 1 for a motor vehicle of that type.

So thats max of $5500 for up to 5dba over, $8250 for up to 15dba over and $16500 for more than 15dba over.

I guess he got off lightly!