Warning, warning, "gay step alert" :lol
Bin it :sly
As for the rest of the guards subject, I'm not convinced they're really needed. Front diff and sump are snugly up over cross member. So front end could possibly do with a big old skool bash guard just to help deflect the truck over bigger rocks. 5mm steel will do nicely. best fix to underside of chassis and up to a steel bumper for rigidity.
Rear diff is pretty beasty on it's own and you'd have to be desperatly unlucky to land it right on to a big enough pointy rock to do any damage.
Rock sliders, as said above , make your own option really. Bin the chocolate sills and replace with box.
Fuel tank is probably the most vulnerable thing underneath I reckon. So for well hard coolness I'd do a body lift and then lift the tank up too. better still get a new one made with a better departure angle profile.
Carry on