Hello again! So my fiesta should get again tüv (18 years old) ….. Since the whole underfloor rusts quite strongly a friend kfz master gave me two possibilities to come through the TÜV and I should choose a possibility. One possibility would be to spray properly with such a kind of spachtel mass and then paint with underfloor varnish and then to lubricate with much underfloor protection. The other possibility would be everything with rust converter very much d after 12 hours rinse off with high-pressure cleaner and look at how stable it is, because thin underfloor protection spray over it. . What possibility would you take and why? Please don’t write that both is stupid, I barely have a cent and need the car urgently. What does the car hold with even longer?