Single-family house, hillside location, basement half residential/useful area - expensive shell construction?

But: should it be cost-neutral to use sand-lime bricks instead of perforated bricks in the exterior walls and take a few centimeters more insulation for that? It would have the advantage that the wall would be thinner and the interior space larger.

If the general contractor builds with sand-lime bricks as standard, then sand-lime bricks are cheaper. If the general contractor builds with bricks as standard, then bricks are cheaper. It’s the same issue as with the air-to-water heat pump and gas. Actually, sand-lime bricks plus ETICS (EPS) is a very cost-effective solution. But only actually. If the general contractor wants to reach a minimum purchase of 200,000 EUR at his brick supplier (bonus!), then he can only make you the more cost-effective sand-lime bricks plus ETICS as a defensive offer...

Residential building: ~1,500 CBM
Double garage: 165 CBM

For the size, the price was great.
What kind of stone do you have with what thickness?

An architect gave me a guideline of €330/m³ to €350/m³ for converted space (turnkey), his last five houses he supervised ended up with these total costs (only the house construction without the land). We would have about 790m³ (external dimensions 8.60 x 9.60, 45° gable roof, 1m knee wall). This results in estimated costs of €268,600.

A general contractor calculated the same house at €275,000 turnkey and €191,300 as a shell house (a different construction company! estimates €260,000 for the same scope of work).

And otherwise:
"If with shell construction only the pure masonry work is meant, this amounts to about €70,000 for you, i.e. about 25–26% (of the total costs). Including the roof, this value increases to about 34% (= about €90,000)."

If I convert this to his 1500m³, that is €510,000 turnkey. Of that, 26% is €132,600 but without roof and without garage and only pure masonry work (no plaster). If the €130,000 figure is therefore correct, then yes, it is very cheap.

At that size, the price was great.
What kind of stone do you have and what thickness?

We are building with calcium silicate bricks.
Price is complete so far, including construction electricity, Dixo and crane.

All foundations, ceilings, rebar, finishes

All concrete stairs 2x inside the house and 1x in front of the house.

Additionally, small things like landings or railings