Just wondered, as a TD5 passed me at lunchtime, and I have a 5 cyl Vovlo, and there are loads of 5 cyl Audis. I remember Audi introduced a 5 cyl years ago. Is the TD5 related to this? It would seem sensible.
The 5 pot engine is smoother than a 4, due to the way the crank works. On a 4 pot motor it wobbles around a lot due to the firing angles or something like that