This is surely interesting as this mod would be so darn easy with a simple dremel and an AlOx Wheel.
I like that dyno chart. The torque is flatter with less irregular bumps, and the HP has a nice climb until it can't breath anymore which isn't anyone's fault. (Except for the Subaru Engineers who decided to make the valves poorly breathing at high end)
I suppose the non-modded header hits it's max flow earlier too since it seems it levels off a lot earlier and lower than the modded headers.
--edit--
Now if we can get rid of the nasty turn before the cat section, we're good to go. There must be a simple way we can cut off the end section and weld together a straight collecter. The cat section would be then lengthened and/or modified to meet the header at the new location. Anyone think or this or try it out on a drawing board? I bet that a exhaust shop would do it cheap if we got it to work.