Have you been in a modern diesel, MB CDI? Go this weekend and check it out. You will scare the guys with your bad A$$ 100 and get a test drive in one sweet machine. Actually, I believe diesel hybrid will be the lead engine in 20 years or so.
I know there's some big Ford I drive by in Ouray that was REALLY quiet. I could tell it was a diesel but barely. He was going up a switchback and on the gas and it was smooth.