I did click save. This time I think I solved. For you guys to know:
Do not tick the "refit" box, the one on the top that marks all parts. Do it one by one instead. It worked with me. I tried this after reading the game guide, namely:
"Beware: parts with an improved design will not be on the car until you click to replace the old part!"
http://igpmanager.com/play/?url=guide/beginner#preparing
The text is ambiguous, but I ticked every part individually and it seems to have solved it.
Try it !
Good races.