the S4 is the mid-level performance version of the Audi A4 saloon. Swapping between twin-turbocharged, supercharged V6 and even a naturally aspirated V8 engine in times gone by, the B9 S4 returned ...

Like its larger S6 TDI and S7 TDI counterparts, the Audi S4 has adopted a diesel engine – at least in the European market. Strange move? Perhaps, but with diesel still a popular choice in this ...