[kyleb]

A possible solution:
You already have the cats fitted which drops the noise level some.
Fit the spiral wound internals with supertrapp ends.
Would be compact and adjustable.
How is the noise test done in W.A and what level do you need to achieve?

I used the magnaflow glass packs on my sidepipes which were ok when cruising but when you stepped into it then it would bark !!
We have to meet the noise level at a specific RPM which is where the ability to tune comes in.
Then you come across the performance/noise issue as well.
Cam changes etc will change the noise characteristics also.