Just wanted to mention the BIG difference between the Ferdi and Elefant, is the zim. The Ferdi did not have zim while the Elefant did. As mentioned before, the Elefant had a machinegun and cupola added along with new tracks. So, basically if you don’t want to bother with the zim, get the Ferdi.
Someone mentioned the Aber fenders. I would not get the Aber fenders unless you plan on bending them. The kit fenders are quite adequate and Aber does not include the full fender in its kit. You also have to purchase the Aber PE for the Ferdi to get the folding mud flaps.