Sanitary offer - realistic & reasonable?

I don't want to do it myself. With such a high amount, however, it's worth checking whether it's worth removing the work from the contract (and thereby losing advantages like warranty, etc).

I understand that, but why do you then choose some no-name component, about whose quality you know nothing? Then just buy something decent and have it installed by whoever, if you can't agree with the general contractor's offer. Your craftsman can easily install it, and for example, with Grohe and others, you get top support.

are the pipes actually all standardized (diameter and distances cold and hot water) so that you can leave them without objects instances, then install the fittings yourself? or do you at least have to know beforehand what you want to use in order to make the appropriate specifications?

I understood that, but then why do you choose some no-name component whose quality you don’t know? Then buy something decent and have it installed by whoever if you can’t handle the GU offer. Your craftsman will install it easily, and for example, with Grohe and others, you get top support.

We build with GU. There is no free choice.

We are building with a general contractor. There is no free choice.

This does not apply to all general contractors. However, if it is like that for you, you may want to consider removing the trade from the general contractor in exchange for a credit. Therefore, I ask you again why you would then install a noname product.

That does not apply to all general contractors.
But if it is like that for you, you might want to decide to remove the trade from the general contractor in exchange for a credit.
Therefore, I ask you again, why would you then install a no-name product?

No, you misunderstood me. If I remove the trade or the installation of the shower, I would of course not choose a no-name product. I wanted to discuss here in the forum whether it even makes sense and whether the price from the executing company of the general contractor is not actually okay.

The topic of price with general contractor constructions is much discussed and you will not find a solution here, also because many general contractor agreements differ significantly. If you have someone on hand who can install it properly, I would take it out and install what I like myself, even if the credit is not that large. But I would also find something sufficiently nice for myself online or elsewhere, max €300.-