Ok so its been a week. Sorry to keep you hanging but I finally got a couple days off from work in a row for once so I did the swap. I found the swap a little time consuming and with the right tools not too hard. So I coated in Black 2000 degree paint. It had the O2 bung and egr bung. I found that the EGR bung isnt useable unless you get the tube from the ranger also. So I ended up blocking my egr off. I tried to get some reasonable proof of any gains. The first thing I found was the weight difference between the massive mustang manifold and the Ranger steel tube header. I would say that the mustang manifold weighs at least 10-15 lbs more. Second thing I noticed driving was the difference in the way my car launched. Before It use bog down if I launched it from a rev. Now I notice no bog and a pretty nice weight transfer. A little test I also ran was a frequent pull I make from one stop sign to the speed limit sign near my house. Its about a 75 yard distance. I always tried to get to the speed limit of 45 mph from a complete stop. I of course launched the car evertime and would get to 40 consistently. After the swap I made it to 44 mph with no trouble. I hope this helps. I am very pleased with my results ecspecially the tone change in the exhuast. It seems to have a bit lower tone idle or rev. It doesnt have that dreaded ricer wet fart sound.
p.s. didn't hollow out the cats