building a prefabricated house in B

Hi, does anyone have experience with companies that build prefabricated houses (constructeurs de masion prefabrique)? Any recommendations from experience, or some to stay away from? I have seen ads from MODULART, can anyome comment on them? Also, I remember seeing recommendations of books/guides as a must read on how to buy a house in Belgium, but cannot find the question. The info I need also needs to include what to look out for when buying the land to build. I did a lot of googling and found quite some information on the house buying but not on buying land and building.
Thanks!