At the time I wrote this there was only a few issues with the upper header, then they got worse. How, I have no idea but the headers got so bad that we could only use them as a repair header and not a replacement header. Then two years ago we got with the manufacturer for over a year trying to find the flaws in the radius of the header. After probably 15 installations of the test product the flaws were finally corrected. The current production of the header not only has the correct radius, it also has the mirror mounting holes in the correct place.
Since doing an edit on the supporting document is a royal pain, I’m placing this not at the beginning of this tech page.
The most common header parts sold are listed below.