OBX has always taken other people's work, and sent it to china to be made cheaper. Quality is never the same as mentioned earlier. We all want to save money when we can, but having to modify a $1000+ set of headers and worry about cracked welds just isnt worth it IMO.
I am obviously a big fan of ARH and run their headers on all of my trucks. I have never had a single fitment issue or cracked weld. They also come complete with quality gaskets, bolts, clamps, and all 4 o2 extensions unlike OBX. Those extensions are $25 each, Gaskets are another $50, bolts are another $50...when you add it all up, you arent far off from the cost of ARH, and are settling for a sub par header.
My advice is to stick with a quality, proven, American made header, even if it means having to save up a little longer to get them.