ITS a Bitch...
I have the JBA Headers, Magnaflo muffler, AFE cold air intake and Edge Evolution....
As far as the headers being difficult to do, I will attest to that...I am very methodical when I do any work, let alone on my F150. The hardest side is the passenger side. The engine mount has to be removed, the starter, trans dip stick, intake tube and then jacked up 1" to gain access to the header/ manifold bolts. Then on the install, you have maybe 2 or 3 bolts that are nearly impossible to gain access too.
Anyhow, this combo works for me...closest thing to the Banks Power Pack before Banks came out with it.