I don't know what shipping cost would be to Greece but when I sold my Bronica 150mm lens on Ebay I got less than $100.00 U.S. I felt like I gave it away. It's a wonderful portrait lens.
The Nikkor lenses are considered to be the sharpest followed by the Bronica lenses and then the Komura's. The exception is the 135mm Nikkor which is known for being soft. I have never shot the Komura lenses so I am going by what I read. If you get a chance to buy the 40mm Nikkor it is a fantastic lens. I sold my well used but with great glass sample for $400.00.
You are going to love the 75mm Nikkor. It was my favorite.
I found really cheap a Nikkor 135. Should I buy it? You mentioned it is soft. Or maybe should I save the money for a Bronica 150?