I'd like to add another pipe as well. Maybe because the Fusion is not a popular car to mod as some others I own and the forums I belong to, but response or help is very limited. It's just an appearance thing, and I get it. I've looked and done some research and from what I can tell it's one of two things. Either get an aftermarket custom bumper or a factory set-up. I'd like to go factory. So I believe it's the lower part of the rear bumper needed, then the modified part (that gray strip) that has the dual cut-outs. Then the two exhaust tips that are attached. A different muffler and of course the two pipes. I can't find enough info if the attaching bumper clamps, holes, hardware would be the same. I wish I could find someone who has done it but plan to do it myself sometime in the next few months.
There is a YouTube video that shows almost all but it's an entire body kit and I'm only interested in the rear bumper. He converts it to a dual look but only one pipe.
Any other ideas or thoughts, I'm all ears.