Well, after months of talking about it, I finally went ahead and had a Magnaflow stainless DI/DO muffler and pipe setup installed, and I couldn't be happier. Fantastic install job by my local Merlin's. They cut out the factory POS Y-pipe and ran two pipes into the muffler, then two 2-1/2" pipes out to behind each rear wheel, mimicking the factory position coming out the side. Had it all finished with a couple Magnaflow slash-cut stainless 3-1/2" tips (which cost almost as much as the muffler!) Didn't touch the cats or O2 sensors, no "Check Engine" lights or other problems like rattles etc. My only regret is that the shop couldn't do stainless pipes, only aluminized, but I've had some aluminized systems last a long time, so we'll see. Seat of the pants--a noticeable gain in performance throughout the RPM range, especially down low! I guess what everyone has been saying about the factory Y-pipe is true. Sound is great too, a nice rumble which sounds cool when I floor it, but not FM loud. A little drone around 1700-2000 RPM, but nothing too obnoxious. For the fellow a while back who wanted to know how to make his F-150 sound like his Cobra, this is the ticket! My wife drives our '97 Cobra, and while it is a little louder and more "burbly" than my truck, my F-150 now has a real "Mustang" sound to it. This is great! I'll try to post some JamCam pix in the future. I'm also going to post about my K&N FIPK that I just put in, and my Pace Edwards PowerGate. Take a look for them.