I gotcha. I have heard the MBRP is an excellent kit as well. But if you want to keep the stock piping some fab work will have to be done I think. The stock muffler is pretty long, at least it was on my 01. So after the stocker is cut out, a new piece of piping will have to be added somewhere either in front of or behind the new muffler whichever one you decide to choose.
Just because I like to modify, a lot lol, any muffler besides the stock one is good except for the cherrybomb IMO. I have never been a fan of those at all.
-2011 F-150 Lariat: 5.0 "Coyote" V8, 6-spd Auto (6R80E), 3.73 ELocker. White Platinum Metallic Tri-coat.
-1992 Ford Ranger: 4.0L OHV, 5spd (M5OD-R1), 3.27 Open.