Exactly. Alex over at Vildini Motorsports built my 3-in. turbo back exhaust for $400 to $450 (I can't recall exactly) and I had to supply the muffler (Borla XR-1). All mandrel bent pipes, custom fit to my exact specifications and car, and the DP has two O2 sensor bungs.
If you think that $500 is too much for a "piece of pipe", you build one and sell it for less.....or learn the skills to do it yourself.