I know this thread's a bit old now but I thought I'd throw my recent experience in here.
I'm driving a 2010 FX4 with a 2" TT and 2" shackles, 265/75/16 Toyo open country M/T's (big aggressive side lugs).
At full turn (either left or right) on flat pavement the tires do rub on the sway bar. Not enough to pose any sort of problem, but there is enough rub that you can feel it through the steering wheel and hear it as well.
My mechanic buddy figures if we put 1/4" spacers on the front wheels that would eliminate it. I might get around to doing that or I might not.
Just some dude from BC...