I sold mine M52B20 for 220€ last winter, here in Lithuania you can get M54B30 for 650€.. But yeah, I know that prices for car relates things are high in Germany, shipping is not an option too cause I am sure it would cost a lot. Swap is mostly plug and play if you know what you are doing and have the place to do so, swapped broken M52B25 in E39 sedan to working M52B25 engine in less than 6 hours few months ago in driveaway, ofc we had engine lift and etc, but the most fun thing is that we got that M52B25 for 150€ after giving old one to the people we bought it from lol. I am sure you will figure things out soon