Audi A6 3.0 TDI Quattro – 242bhp

Classy though the A4 is, the refined elegance of the A6 (updated in early 2011) is worth the stretch if your budget allows. There is plenty of oomph from the 3.0-litre oil burner that does service in this model, and also powers the A4, A5 and A7. It hits 62mph in 6.1 seconds, yet it is refreshingly clean and frugal.