Compared with the Bergepanzer III, the Bergepanzer IV was actually a rare vehicle, with only 21 built. The conversion work on the real vehicle was quite simple, and it is thus not surprising that the same can be said about this set. The conversion is mainly limited to a wooden deck where the turret once was, a winch and a massive wooden beam.
CMK goes that little bit further by also giving the modeler other parts to update the Panzer IV, be it in it's Bergepanzer or Panzerkampfwagen guise. This means you get some PE update parts (e.g. handrail, spare wheel holder, fender flaps) and a full set of new resin wheels. I am not quite sure why these are given, but they will allow you to backdate the wheels of the Revell kits (which is the suggested donor kit, although I guess that any kit will do) to the earlier style hubs. Under the assumption that older PzKpfw IV hulls were used for this conversion, this makes sense, although they might not be necessary.

Overall quality of the parts and of the manual is very good, as usual from CMK.