Why are you changing the front calipers? Unless there is something wrong with them, leave them alone. Oh, and change the whole system brake fluid with the MB DOT4+, it works best. 85w90 is perfect for the diffs, no LSD additive needed, they are open units.

As for fuel filter, depends on which one you have. If the upgrade was done, it is easy, if not, you will spend several hundred to do it, and you HAVE to do it, as no one sells the old style filters anymore.