I have a truck that I run on WVO, so I guess I think it is worth it.
As for old Benz's, I have one. I bought it to convert, but even if I weren't going to convert it, I would still want to drive a car like this. I like it because it is so reliable. Any 1979-85 5 cylinder Benz is bulletproof. They made 2.6 million of these cars. You can still get any part you need.
Want a cheap conversion?
http://biodiesel.infopop.cc/eve/foru...322#5131092322