Hey mate,
I was looking at RMS, and was initially going to take it there, and then to Speedworks. No offence to people out there who get exhausts off Ebay and the like, but i don't think the quality is there, and if it is, it's very rare.
I have recently had a
TBE fitted, full 3" all the way, mandrel bent, stainless steel and it's oh so sweet. Cost me $2200 fully fitted, but glad i spent a bit extra to get a quality system.
This is what it looks like, before/after. I have contact details for this bloke. He'll get the exhaust made up for you (custom made) and he'll fit it himself in a day.
http://members.ii.net/~tcarch/WRXExhaust
Damn happy with it and sounds the shiznit!~