We had a new ST TDCI at work, and beautiful car. It was brand new sounded quiet and drives well until about 3000 miles the engine sounded like a tractor engine, we took it back in and asked whats wrong with it, they said nothing thats how they sound after run in period

We got a Audi A4 sportline diesel in now and about the same speed and better handling.

But IMO you cant beat a Golf GT TDI 150, now thats a proper diesel engine, quiet even after 13k miles, pulls really hard right up to the 5k rev limit, shame about the interior and the worst handling i have ever driven in a new-ish car