Had the mod bug when i saw other members rides on ClubCJ

first mod i did to my CJ was window tinting and debadging of the 'LANCER' and 'ES' badge on the rear bumper.
planning on getting a cat back exhaust for my next mod. probably a 2 1/4" cat back as i have read that it gives better gains for our N/A lancers. Does any one recommend a good muffler and fabrication shop in the Liverpool / Sydney area?
Thanks,
Au3