i think it is by appointment only at the moment and i would go there when they have one or two interesting cars ^^. My dad would come also, but he is vaccinated. I will tell you if we come, would be nice to see the 300zx, but we could drive you no pb

I think that you've made the correct decision.  There was something wrong with that car.  I also think that there's been collision damage. 

Rust repair for Z's is not easy, but there is a lot of great guidance available for DIY-ers.  Conversely, you may observe that there is virtually zero guidance available online -- on this site, or anywhere else -- for home garage correction of collision damage.  Worse still, it can take some careful inspection to spot collision damage.