When I ran BFG 32x11.5R15 AT's, I had around 3" starting off. The tires will rub your stock flares at full stuff. I was still able to rub the flares with another 1.25" lift. But really this will depend on the lift and how stiff it is. If you don't go offroad then 32's will clear with a minimal amount of lift.
I agree for 32 SS's I'd go with 3". It doesn't matter how you do it. 2.5" suspension, .5" shackles, 1.5-2" TJ flares... If you don't run trackbars and disconenct the swaybar you'll want to extend the bumpstops as well.