i run advanced extractors, with magna flow high flow cat... 2.5" stainless steal system with one genie turbo muffler..
make sure you FIT A CAT!!! even if its factory.. they make such a tiny difference that its not worth screwing up the environment for, as well as there being a MASSIVE fine if you get caught with out one.
(all it is, is a piece of honey comb style mesh, with heaps up bright red, burning excess fuel and crap, so as you could imagine, unlike the old wives tale it makes stuff all difference, if you must, go high flow)
AU2 S-pack Owner: Silhouette Black, XR6 Wheels, Tickford Sunroof, C2R rear bar, Checker Plate Floor Mats, Chrome Door Sills, Blue Backlite Dash, Blue Painted Brake Callipers, Advanced Extractors, Magnaflow High Flow Cat, 2.5" Stainless Steel Mandrel Bent Custom Exhaust, Genie Muffler. Sony Explode 50w x 4 deck, Kenwood 140w speakers (front and rear), Boss 1200 watt Amplifier, 12" Orion Sub in custom box. More To Come!!