Someday when I find a station with biodeisel I am going to try it in my 300DT. The main problem around here is no one sells biodeisel. I think you guys would be very surprised at what a old diesel benz will run on. They had a thread at
www.mercedesshop.com about what you have used instead of diesel, guys had run them on motor oil, transmission fluid, pretty much anything you could get into the tank the car would run. I am not that brave as new injection pumps are very expensive and mine is a low mileage car so I don't want to mess it up. I do hear they run much smoother on bio compared to low sulfur diesel--one day I will find some and try it out. Here is a picture of my other German toy.
It has been a fun project and is actually now a semi daily driver--not bad considering the old girl had sat in a barn for three years.