Hi Kent,
I went to the SA.gov.au website and looked up Transport, Exhaust Systems and noise. This is what I found
SA.gov.au website:
Transport: Exhaust systems and noise
Modifications to exhaust systems are permitted if they do not conflict with the requirements of any other rules or regulations.
Vehicles also must meet the following requirements:
Vehicles may be fitted with extractors provided that any emission control devices which were originally fitted to the original manufacturer's exhaust system, including catalytic converters, are re-connected and operational.
The extractors must not foul any part of the steering, suspension, braking or fuel systems.
Catalytic converters and exhaust sensors that have been replaced are to be positioned in the same exhaust flow location as in the original system.
The exhaust outlet exit must be behind the last door or window opening on the side or rear of the vehicle.
The exhaust outlet must be as close as possible to the outer edge of the vehicle, but not outside or underneath the vehicle.
If the exhaust system is not underneath the vehicle and can come into contact with people, it must be shielded.
The exhaust outlet must extend at least 40 mm beyond the furthermost outboard or rearmost joint of the floor pan that is not continuously welded or permanently sealed and which could permit direct access of exhaust gases to the passenger compartment, but not beyond the perimeter of the vehicle when viewed in plan.
The side exhaust outlet must discharge to the right hand side of the vehicle and downwards at an angle between 15 degrees and 45 degrees from horizontal.
The exhaust outlet, if to the rear of the vehicle must discharge at not more than 10 degrees above or 45 degrees below the horizontal.
The vehicle must have 100mm ground clearance.
Extractors and aftermarket exhaust systems may be fitted provided that the sound levels specified in the Road Traffic (Light Vehicle Standards) Rules 2013 Rules are not exceeded.
For passenger cars, passenger car derivatives and panel vans manufactured:
before 1 January 1983, the stationary noise level when tested must not exceed 96 dB(A)
on or after 1 January 1983, the stationary noise level when tested must not exceed 90 dB(A).
That doesn't help much with left hand exiting exhausts, but it clears up that so long as an exhaust exits behind the last door, it should be OK on a Cobra. The bit about 40mm beyond the rearmost joint refers to the floor pan only, so as that is sealed from the cockpit, it should not be a restriction to your exhausts.
So what about left hand exiting? I phoned Regency, Transport Services Division and spoke to Vehicle Standards. I was told that left hand exiting exhausts were now allowed but couldn't be given a definitive reference for the allowance. I was just told that the requirement had dropped out for MA class vehicles. However, the guy also said that the vehicle had to meet all appropriate requirements of the Road Traffic Act, and this still states that side exhausts must exit on the right. So it may or may not be OK!
The conversation ended with the advice that, if I wanted a definitive answer, I should send in an email to:
dpti.vehiclestandards@sa.gov.au
I might just do that, though it won't save me the $850 I paid to have the pipes run to the back!
Cheers, Mike