The Magnaflow muffler is a straight-through perforated design. It is very free flowing, much better than the stock muffler.
Installation: It was pretty straight-forward. The hardest part was removing the stock exhaust. The nuts on the stock hangers are on there pretty tight, but it's manageable. First step is to loosen the stock hangers on each side of the muffler.
After loosening the stock hangers you can remove the rear section. It helps to twist back and forth to help generate power to slowly slide the rear section out. The fit is pretty snug, but twisting back in forth will allow you to remove it a little bit at a time. Once the rear section is removed use the same twisting motion to remove the stock muffler. Be careful once the stock muffler is removed because it is heavy and you don't want it to fall on you. Here's what everything looks like after moving the stock muffler.
After removing everything I also took a few pictures of some of the stock components, for those who are interested. Here's some pictures of the stock catalytic converters and the incredibly restrictive y-pipe. I had no idea the y-pipe was this restrictive. I might change that in the future.
Now install the Mufflex muffer. The fit isn't perfect (as other's have noted). The front end fit good and there were no issues. You can tell it doesn't match perfect to where the stock muffler lined up, but there is no leak, so I don't care.
The rear side of the muffler is a different story. The fit was very poor and I can not manage to get the rear section to fit properly. There is a small leak as a result. I tried for a long time but couldn't manage to fix the leak. I tried to relocate the clamp to different spots, but it did not fix the leak. I also tried driving it for a week and working on the leak issue again, but still no luck. I will eventually take it to an exhaust shop and have them give it a try, and if they can't fix it I'll have them weld it.
Sound: Mufflex describes this size muffler as a 9 out of 10 on a loudness scale. It is much louder than stock, but I wouldn't rate it as high as a 9, more like a 7 or 8. I was looking for a loud exhaust, so this was actually a little disappointing. The sound is still very good and the exhaust note is very smooth. It has gotten louder as the muffler has broken in, which is a good thing. In the cabin the sound is very tolerable, but I know some people don't want to hear their exhaust in the cabin, so they would probably be happier with the 18 or 24 inch muffler.
MDS: I was a little nervous about how the exhaust would sound while in MDS, based on other reviews. I have to say the sound it not good, IMO. When MDS kicks in there is no doubt about it, it's very apparent. The sound gets very deep and there is a lot of drone. At certain speeds the sound reverberates and gets annoying. When driving mostly city, I prefer to drive with the truck in 5th on the manual shifter so MDS won't activate. When I drive on the freeway I put it back into full auto to help with the gas mileage. The MDS issue might not be as bad on the larger muffler (18" and 24"), but with the 14" muffler it's bad.
Performance: I didn't get any dynos done, so I have to go by the reliable butt dyno, which feels like there is a small power increase. I didn't really expect much and did the mod mostly for sound, so any power increase was a bonus. The only slightly objective data I have it that now I can break the tires loose from a dead stop, which didn't happen on the stock muffler (thanks to 3.21 gears).
Overall: I would give this exhaust and 8 out of 10. The exhaust sounds really good and makes your foot turn into lead, dunno why. The fitment could be better and the MDS issue might be a big turnoff to some. I would recommend this setup to someone who likes loud exhausts and wants a nice DIY option.
Now, what you all really want, the video. It's kinda long but I wanted to include a nice before and after comparison. Enjoy.