Scotty is in Melbourne. If you need it fitted in Adelaide talk to AM Performance, Andrew is happy to install Scotty's gear once it arrives.
If you want to replace the rear too, which I don't think is quite as urgent, see what Scotty can provide, talk to Andrew at AM, or get a Jap exhaust.
I haven't had any dealings with Sinergy, but haven't heard anything particularly good. These cars are easy to service yourself, most people seem to DIY, so I wouldn't bother taking it back there.