OK everyone, sit down and hold on tight for this one ... I agree with Zeus.
The diff drop does NOT decrease your ground clearance at all. The associated crossmember drop does but I'd personally rather take a hit on the crossmember than just about anything else under there.
The loss in ground clearance is probably much more pronounced on mine than anyone elses since I have the Calmini crossmember. Someday I'll modify it to get back some of the ground clearance - it's just not high on my priority list. Let's just say it'll be done before I get to Moab
Actually I've been thinking that rather than raising the crossmember back to a more protected area, the better approach would be to fab a small skid plate to it so that if it gets hit, it'll just lift me over the obstacle without damage (other than abrasions).