Indeed 6 cylinders diesel engines do not sound like tractors anymore and can be quite powerful (i.e. BMW 535d).

I had myself a BMW diesel but I was clearly missing the petrol engine sound and high RPM use of the engine which makes it (to my point of view) much more fun to drive.

I'm sure the debate petrol vs. diesel engine is not finished and that, in Europe, the Cayenne diesel will be more sold than any other Cayenne in the coming months, especially with all these eco taxes!