I'm talking about the rear muffler, replacing that with two. Hooker aero chamber mufflers are sweet but wouldn't fit at the rear, and are slightly tricky to fit in the center of a commodore, as you really need offset in and out. And more expensive.
I'm surprised to see the exhaust uses slip joints at the back, that's a bit crusty. A proper bolted flanged connection like factory (and xforce ) is heaps nicer.