I was talked into the 2.66 with 3.55 rear and 487whp / 482trq.. it was a DOG.
I swapped in 4.10s and it's ok, but the oem TR3650 and 3.55s were faster in the 1/4.
I'd go with the 2.97 if I could do it again.
Sometime in 2008 (I think) Ford did away with the midpipe hangers. So I don't think they are needed.
My Oct 07 build, 2008 had the hangers on the oem mount but did not have them on the OEM midpipe.