I would consider the Audi A3 TDI to be a direct competitor. It carries a 2.0L I4 turbo-diesel. It has a horsepower of 140 hp @ 4,000 rpm and torque is 236 lb-ft from 1,750 to 2,500 rpm. It retails for $37k, which I think is what the 2 Series diesel will probably retail for.
The 2 Series diesel would also compete with its own 3 Series diesel.