I know a good bloke in dandenong if you're interested. In behind Pedders, right up the back, next to the car detailing place. My family has known him for about 15 or so years and he is a real master of his craft. Quite reasonable on price, too...
As for the exhaust, take it from someone who's had both a 2.5 and 2.25... for what you want, i'd get the 2.25 and some lukey extractors.
This will give you a more noticable increase down low and nice responsivness. IMO genie extractors aren't anywhere near as good as they used to be.
Make sure you get straight through mufflers, and because they pose no restriction, you can just keep adding more until it's quiet enough to suit your tastes.