Very well written and very informative based on whats out there.
Only thing I noticed was the way you wrote it in the blog you made it sound as if Ford did nothing to the Mustang engine from 1996 to 2011, which is untrue.
the SN-95 mustangs in 96-97 used a 4.6 2V rated at 215HP, this was then revised in 98 to bump it to and impressive 225 lol.
in 1999 with the "New Edge" refresh the 4.6 2V was revised again to see an increase to 260HP. The way its written in the blog makes it seem as if Ford continued to use this 4.6 from 1996 to 2011 before the 5.0
The 2005 Mustang saw the introduction of the 3V 4.6 wich was rated at 300HP. When the resfresh happened the 3V was increased to 315HP. Then in 2011 the 5.0 was released at 412 then raised to 420.
You predicted that Ford will add direct injection and some tweaking to the 5.0 and increase HP for teh next gen which looking at their history is pretty much spot on.