We also dealt with the topic of prefabricated houses last year and checked out all the providers. They also tried to pressure us into a quick signature, which fortunately did not work. After many comparisons, it was easy to see why we were put under time pressure.
Do yourselves a favor and take your time. You will probably never make such an expensive purchase again.
Our planning started in May 2015, we took a lot of time and thought everything through carefully. In the end, we switched from a prefabricated house to a solid house and from a company to an architect. So completely different from what we initially wanted. Now, this Thursday our base slab will be poured.
Wishing you good luck and perseverance!