Bring a backpack when you drive the Audi S4, because there’s precious little space to stow cell phones, sunglasses, iPods, packs of gum, and all the other detritus of daily life. The door pockets and center storage console are the main places to stash stuff, but neither is particularly accommodating. The glovebox is large, but is crammed with oversized documentation and a CD changer. That leaves a thin slit of a tray in the upper dash, the cupholders, an almost useless recess in the center console, and the twin rear nets on the front seatbacks. Also, though the S4 convertible has four seats, it contains just two cupholders.