I have a Borla XR-1 Catback exhaust for sale.
This catback will mate with the stock downpipe but it also has a 3" adapter to mate with aftermarket downpipes. It is not too loud, but it is not quiet, youtube it to get an idea of how it sounds, it's a nice deep tone.
There are plenty pictures of it here: http://picasaweb.google.com/orangebroccoli16/Untitled#
I would like $420 for it, picked up.
Here is more information about the exhaust: http://www.jscspeed.com/wrx/exhaust/borla.htm
I am in Whippany, Northern New Jersey.
PM me or just post here.