Hi,
You can sell your original mat to me if you don't use it lol.
But if your trunk seal is good there shouldn't be any form of condensation.
By the way i was thinking of a thick black carpet material to be cut and embroidery border instead of rubber which looks great.
Cheers
I am not sure if condensation depends on seal quality, I would have thought it is not. As WRe is saying: you will have more condensation with rubber mat on the floor.
I understand the need to have the original rubber mat (I was lucky to still buy it from Mercedes for about $100 at that time), but you may want to consider packing it and putting it on the shelf and use the carpet in the trunk.
In any case - the prices will be high for an original one...
As for water presence in the trunk (not from condensation), my suspects would be seal, emblems, lock and the star. Well, assuming there are no holes in the floor.