I know Kevin from the Second City Conservatory Program and we have both performed many shows together over the last year. Somehow through all that time, I never saw his car, so I went to see it today. Kevin's diesel Passat was converted to a two tank veg oil system. He showed me how it works and we went to several restaurants to collect oil. Not too difficult. I might be able to do this if I had a place to store oil. Can't really do that in an apartment, and since we have carports, we're not allowed to keep anything in it aside from a vehicle. Kevin lives too far away for me to use his garage as a filling station.

I'd tell you more about Kevin's car, but he has a blog about it which is worth reading. Kevin bought his diesel car off Ebay without test driving it. He's had a few problems with his conversion and he occasionally does some new modifications to make it work better, but don't let that scare you.
See Kevin's blog.