I understand what you're saying in theory, but I'd be surprised if an extra 1.5ft of the same sized piping as the turbo outlet with no restrictions would add any back pressure at all. You might be right though. I just don't see it. My boost is exactly the same, and the power doesn't feel any different at the low/mid/high end. If I was to add a cutout, it would be about 1.5 ft in front of my tailpipes, and would be the same sized piping. .

Here's another look at the piping off the Y-Pipe. Y-Piping The pipe is actually slightly larger than the Turbo outlet as it can slide right over it.

I know adding a muffler after the turbo would really restrict it though. I don't see the purpose to that as it's not loud anyway.