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 ...

In fact, only the boot lid, roof and bonnet are shared with the current B9 A4, signalling the importance Audi is placing on ... the latter powering the new S4 TDI. Three petrol versions are ...