The only real issues with newer VW is in the electronics. I get small little rattles now & then in the dash... stuff like that. The engines are VERY reliable... the duty cycle is way beyond any gas burner. The bodies are galvanized steel and will never rust. Get leather seats and your interior will last too.
I don't know why you would convert your car to run on veggie oil when you can simply mix it in a barrel with a little methanol and lye to make nice bio-diesel that can go straight in the tank. That settles all the glycerine and sludge (if you're using used fryer oil) to the bottom.
New diesels are very clean, and when sulfur content goes down in the next couple years by federal mandate they will be even cleaner. Low sulfur diesel will open the doors to the newer, even more efficient engines they have in Europe now. The diesel here is just too dirty now for them to run.
I wouldn't recommend an un-proven technology like hybrids. Where do you get maintenance and how much are the parts? Any mechanic can work on a diesel and parts I'm sure are cheap... not that diesels break much.
Now what I would like to see is a Diesel Hybrid!!
