So…
The issue was that the hardtop just refused to align in height.
Put it on, many times, tried whatever trick, and finally after many hours comparing it to the other one we had available, discovered that the rubber seal on the bottom was not the original one but a random “do everything-fit all” one that not only could not be compressed but was also 3 cm thicker than the correct one.
discussed it a lot, and finally decided to fit the black top that fits and my friend will get my silver one as it is the correct colour for his car and just change the rubbers.
My car is titanium silver and the the top I had was a grey-ish lookalike but not exact match.
his is a dark grey car and my top looks better on it.
So here I am with a black top… that fits… (better)
case closed.
Also had the opportunity to see a strange E39 with an E46 S54 engine, one of the weirdest transplants ever…