I like the mid muffler, but in my experience (yes, actual experience) and a co worker with an 07, the mid muffler is not a bolt on kit, no matter what the manufacturer says. best to leave it to a muffler shop. my install was $150, that required alot of cutting, and fabbing of hangers to make it fit right, not touch, and not stick out too far from the bumper.
I had magnapacks and now a hybrid midmuffler set-up (12" bullet mufflers/resonators) welded before the axle and SLP LM. Both have an awesome sound. From the inside there is not much difference in sound except the magnapacks droned more. I would get a different mid-pipe. I would go with either a catted x or a prochamber and have hi-flows welded in.