LED Spots

Hello everyone, I am planning to use LED spots in the living rooms of our small 123sqm single-family house.

My best buddy (electrician) recommended using high-voltage LEDs because then I don't need a transformer anymore.

We have to plan the spots directly into the concrete ceiling, as a suspended ceiling is not possible.

For the LED spots, the mounting boxes have to be somewhat larger than for halogen or regular lamps, and so far I only know the Kaiser Halox O and Halox P boxes. Are there possibly cheaper alternatives?

I searched for a long time too. But found nothing. So bite the bullet and spend the money.