The Audi S4 (B9) delivers serious performance, luxury, and everyday usability—but is it so good that you don’t even need an RS4? Join me for my first drive as I put this sports sedan to the test!

Diesel's low-rev response, some fussy facelift styling details Understated almost to the point of anonymity, the S4 is the mid-level performance version of the Audi A4 saloon that’s seen more ...