The exhaust was pretty simple, I took my complete M4 system, ditched the midpipe, and shortened the muffler. I had a local muffler shop expand the muffler inlet to fit over the collector outlet and voila. I haven't had it on the dyno yet, so I'm unsure what this did to power. It was definitely a form over function thing so I'll have to live with any negative results. Feels like normal on the road however.