I decided to get rid of the stock exhaust system and get a 4" turbo back from Diamond Eye. The model number is K4324A in case you are interested in doing the same. I had a pretty hard time finding the part and even Summit couldn't help me, so I hope this reference makes things a bit easier for some of you.
I would highly recommend a heat shield (see pic below) if you are going to put that size system in. It is very close to your transmission and it's better to keep your tranny fluid away from picking up all that extra heat. I also wrapped my pipe with performance heat wrap that you would wrap an exhaust manifold with. It helps keep the noise down and I believe is well worth the cost.
The install is very simple and took my buddy and I about 1.5 hours to do. Make sure you wear goggles because you're gonna knock a bunch of dirt in your face when doing the install. The brackets worked well until the last hanger, where we had to take it to the shop and modify it a bit. Though it only cost $25 to weld it together.
As for performance, I feel a bit more power, but did it mostly for MPG which I didn't really gain much either. Believe it or not, the front cab is quieter, maybe because the air is less restricted, but the back has a slight drone noise that stops after you get out of 2nd gear. I think it sounds good.
Here is the link to an install video I watched before did it myself. Should help a bit. Thanks to the guy who put it together by the way!