Hello, I hope you can give me some tips and suggestions.. My uncle has a new Fiat Ducato Maxi as a company bus and he wants to preserve the entire cavities and spray the underbody with underbody protection. Does this make sense with a new car? Or only after 2 or 3 years? Furthermore, he wants to cover the side walls inside the cargo space and fill all cavities with 2 components PU foam. First because of the thermal insulation and second because of the stability t. What do you think about foaming the cavities in the side walls? What alternative insulation methods are there ?? Stone wool granules? Styroporgranulate? With PU foam I have concerns that the outer skin could deform due to the expansion. Thanks already! LG David