Just to clarify,
I have a 2011SD F-350 Diesel, CC, SRW, LB.
According to Ford this set up has a GVWR of 11,400lbs and a payload cap. of 3950lbs.
They also state that "..springs are computer selected according to package ordered"
Now, They have a 10,000lb GVWR pkg (no cost, but I did...