Land purchase – Which plot makes more sense to build on? Tips

I can't quite imagine a house on number 4 visually at first.

House just like on the plan as well. Move the garage/carport slightly to the north and you have the entrance in the east. This creates a nice south/west orientation of the garden. Or the garage on the southern boundary. House as far east as possible. Entrance in the south or east. Then you have a nice west orientation of the garden and shaded north side during strong sunlight. It always depends on what you prefer. I see absolutely no problem there.

The two plots are subject to practically the same regulatory framework,

Not really.

Ground area and floor area: Main building: Max. 150 m² ground area (from 500 m² plot size). Floor area: Max. 375 m², with 2 full floors.

That applies to floor plan 4, floor plan 5 can be built with 100 sqm ground area.

but has a significantly wider driveway.

Both driveways apparently will be built equally wide. What do you want to build? And for whom? If you want to build a bungalow, then the smaller one is probably out. Ultimately, the textual provisions of the development plan are missing, where there could still be restrictions defined.

Not really.

This applies to floor plan 4, floor plan 5 can be built with 100sqm of floor space.

Both driveways are apparently designed to be the same width.

What do you want to build? And for whom? If you want to build a bungalow, then the smaller one is probably out.

Ultimately, the textual provisions of the development plan are missing, where restrictions could still be defined.

Would build for myself, the idea was a two-story cube house.

Would build for me

Oh.. it's about the question whether for a family with 3 children or for a couple or something. Are you a cyclist or do you have 3 cars? Do you like a garden or do you just accept it for a house? And then ultimately a budget question. Otherwise: the lower one is a bit more open to the street, so you also have to shovel more meters of snow,

Oh..
it's about the question whether for a family with 3 children or for a couple or something like that.
Are you a cyclist or do you have 3 cars?
Do you like gardening or do you just accept it for a house?
And then ultimately a budget question...

Otherwise: the lower one is a bit more exposed to the street, so more meters of snow have to be shoveled,

As of now, two cars, no children yet but they will follow. I naturally like the garden, it's always like a bit of vacation in the summer.
The corner plot would cost almost €50,000 more, that shouldn't be the deciding factor.

Not really.

The quoted sentence also continues after the comma:

but buildability makes a jump of 50 sqm floor area at the threshold "500 sqm plot area."

.

I would build for myself, the idea was a two-story cube house.

With a floor area of 100, that would be about 160 sqm "living space," with a floor area of 150, correspondingly 240 sqm living space. It would be helpful to know what is meant by floor area here. The aforementioned numbers refer to the house's floor area. If garage and access paths were also meant, the absolute value would basically correspond to a (otherwise decimal-noted) floor area ratio I, which could become quite small. Therefore, one must always read more than just the site plan and its legend. You can work around the regional peculiarity of specifying the buildability measure as a floor plan instead of a floor area ratio – more decisive is the explanation of which areas are included in this value.