The swedish magazine TeknikensVärld have tested Audi A4 2.0TDI, BMW 320d and Mercedes C220CDI. Result:
1. Audi A4 2.0TDI (143hp/320Nm)
2. Mercedes C220CDI (170hp/400Nm)
3. BMW 320d (177hp/350Nm)
Price is the main reason for Audi's placement. BMW has the best engine by margin in the test.
Test av Audi A4 2,0 TDI, BMW 320d och Mercedes C 220 CDI
1. Audi A4 2.0TDI (143hp/320Nm)
2. Mercedes C220CDI (170hp/400Nm)
3. BMW 320d (177hp/350Nm)
Price is the main reason for Audi's placement. BMW has the best engine by margin in the test.
Test av Audi A4 2,0 TDI, BMW 320d och Mercedes C 220 CDI

BMW started it but seem improve the interior with their Facelifts instead.