Scurvy,
The mods for the SFP include the following:
Flight spoilers to be capable of 60 degree deflection on touchdown by addition of increased stroke actuators. This compares to the current 33/38 degrees and will reduce stopping distances by improving braking capability.
Slats to be sealed for take-off to flap position 15 (compared to the current 10) to allow the wing to generate more lift at lower rotation angles.
Two-position tailskid that extends an extra 127mm (5ins) for landing protection. This allows greater angles of attack to be safely flown thereby reducing Vref and hence landing distance.
Main gear camber (splay) reduced by 1 degree to increase uniformity of braking across all MLG tyres.
Reduction of engine idle-thrust delay time from 5s to 2s to shorten landing roll.
FMC & FCC software revisions.
There may be others that I dont know about but I would doubt that they would be significant. My point is that none of the above should have any effect on stall margins on a clean wing.
S&L