Model . 2004 Volvo V70R . 2004 BMW M3 . 2004 Audi S4 . Engine . Turbocharged 2.5-liter inline-5 . Naturally aspirated 3.2-liter inline-6 . Naturally aspirated 4.2-liter V8 ...

It was all that stood between them and shoehorning this melodious, 4.2-liter 4-cam 40-valve powerplant into Audi's smallest U.S. offering to create the 2004 S4.

The car apparently retains its original 2.7-liter twin-turbo V6 engine that pushes 261hp (265PS) and 295lb-ft (400Nm) of torque to the ground. In this form, the stock Audi S4 B6 needed 5.6sec to ...