Hey mate,
A lotta places will tell you the Alloytec's sounds sh*t with a catback, but I got mine done at The Muffler Man in Prahran, guys name is Trevor. They've built a custom exhaust system for the Alloytec's (SV6's specifically, I'm sure it would work fine on the Utes), has an awesome overrun noise on releasing the throttle.
I got my Growler CAI done at the same time, so he packaged it for me for $1300, I think the Exhaust System was $700.
He can also tune the exhaust to as loud or as soft as you want (I'm going back to get mine louder soon

)
And the government? F**k them and their Nazi-like traffic control. I've always told them it's legal and technically not an engine mod. 75% of them don't know what they're talking about so you can b/s your way through anything they say.
Good luck, let me know if you get it done.