I pulled the trigger finally & did a completely custom fully welded long tube header setup and am very happy with the initial results.
I purchased the main components (below) for a total of $610 and had a local shop install for $1300 (screaming deal for that kind of custom work) who added a CAT and did all of the rest of the tubing in 3" stainless mandrel bent single run after the Pace Setter provided Y. All done for less that $2K which is what it would have cost me to have the Ford dealer replace both exhaust manifolds with stock parts. One was leaking (broken bolt) and I figured the other side was likely to go too, so this way I took care of both sides for and for the same price made a marked improvement!
Truck has a beautiful low rumble you can only get with long tubes, though the Magna Flow leaves it fairly loud for my taste, but I was going for minimizing flow restriction so a straight through Maga was the choice. Most out there who want custom would likely not think its too loud though.
I chose long tube to have the bigger impact on added HP for towing & MPG for commuter travel. I can tell the truck is much more responsive now. Haven't driven the truck much yet (got it back yesterday) and haven't towed with it, but it has noticeably more jump. Much more likely to inadvertently bark the tires when leaving a stop sign and such.
So far so good, I like it.
I went with these:
Pacesetter Long Tube headers
Pace Setter Y-pipe