Hitech in Sydney do a quality exhaust and even advertise one for MY09 WRX
http://www.hitechmufflers.com.au/pro...F+STi&b=subaru
Verso flash tune at ASG for $990 on top should see the total cost kept under $3K I reckon.
If you wanted to keep the price down a bit more then just get a centre pipe made locally. Nik at ASG can do this for you.