Separate awarding of windows and shutters - GU resists!

In his indescribable way, @11ant wanted to make it clear to you: Definitely don’t do that. It will end in a catastrophe including a financial disaster! PERIOD

Wow, what a blunt shortcut translation ;-)

I have to add that this year it has become fashionable to order windows according to the plan and not by measurement, because window delivery times were (are?) in the range of 9-12 weeks. Compression tape and foam take care of it...

Neither compression tape nor foam are intended or suitable to fix every excessive abuse of tolerances!

Neither compressible tape nor foam are intended or suitable to remedy every even the most excessive misuse of tolerances!

the three dots were for you ;-) I hope the blood pressure is still within limits.

Is production still done in advance according to "standard"?
Regardless: I don't understand anyone who haggles over 10% and chooses a third party.

As said, you negotiate with the GU, show the offer and try to squeeze something out of the other offer.

Besides, you never have the guarantee that the other window installer will show up and then also want extra charges, or not adhere to the schedule because skilled personnel is missing/sick etc.

I would always favor the GU and suggest something.

Is "standard" still produced in stock?

No stock, but batch goods for large buyers such as hardware store chains. , if I remember correctly, used 110-series hardware store standard windows.

Do I understand this correctly??

Despite a saving of approx. €3000 and an additional added value for the lift-and-slide door of approx. €2500, 5 additional electric roller shutters, and extras such as mullion and app control – so overall this makes an effective price difference of about €10,000 or 30% – should we better leave the window and roller shutter trade with the general contractor?

Reason: There will only be problems (agreements, timeframes, warranty, etc.)

You would:
- rather talk to the general contractor again and try to renegotiate (free) extras
- send the offer (I had even done that already)
- suggest that the general contractor can work with a “cheaper” profile, e.g., with Gealan, Salamander, or Veka
- possibly retrofit the electric control of the roller shutters ourselves (but then the roller shutter strap would always be openly visible, right? If I were to order it directly electrically, exclusively the control elements and not the straps would be visible. Or am I making a huge mistake there?!

We will not set up a complete smart home, so we also don’t have a planner to fall back on.

Thanks to you all for the many answers.