Buckle up, gearheads, because we're diving deep into the heart of Audi's B9 generation A4/S4—a tuner's paradise ... Carbon Fiber Mirrors & Flat-Bottom F1 Steering Wheel Canadian Auto Performance ...

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 ...