Standard land value developed or undeveloped and drainage

or I have to invest half the property value again in the development.

You can also just ask the utility providers. It’s only water, sewage, electricity, telephone.

Yes, it does, at least as far as I can judge. But since I am not an expert, I have now made an appointment with an architect, otherwise everything is too uncertain for me. Hopefully, he will be able to assess whether it is overpriced, fits, or if I have to invest half the value of the property again into the development.

Be sure to try to familiarize yourself more with the subject matter, otherwise you will never have the chance to timely check here or there during construction whether what xyz is doing is really correct. You shouldn’t blindly trust the experts. Most has already been said about the standard land value. But I am somewhat confused about how one could come up with the idea that this might possibly represent the price including costs for leveling. Do you come from a very flat area? Depending on where you look in Germany, most plots have a slope and the houses are largely adapted to the terrain.

Most has already been said here about the standard land value. What puzzles me a bit, however, is how one could come up with the idea that it might possibly reflect the price including costs for leveling.

Hehe, yes, apart from the fact that "leveling" here probably means grading, the term "ready for construction" never means a "kitchen-finished" cake base (top edge of the floor slab) on which you would only have to place a house. But what confuses me is the approach of the original poster at all:

The neighbors of the apartment building we currently rent in want to separate a part of their property. We have registered interest and have to decide very quickly whether we want the land.

You can hardly have a closer connection to explore "your" property (and you should already be a customer of the same utilities in the neighboring building). By now, one could have long since looked out the window with a camera and, literally, given the local community a picture of what we are even speculating about here.