The cabin of the Audi A4 and S4, while beautifully appointed and comfortable for front-seat passengers, is a little snug for those in back—especially with respect to legroom.
By the numbers, the A4/S4 sedans measure up at 185.1 inches in overall length, and ride on a 110.6-inch-long wheelbase. The EPA specifications list front-seat leg room at 41.3 inches, and back-seat leg room at 35.2 inches. Compared to the top-rated sedans in the segment, the Cadillac ATS and BMW 3-Series, the A4 slips right in the middle: the ATS is shorter in both dimensions at 182.2 inches long, with a 109.3-inch wheelbase, delivering 42.5 inches of front leg room, and 33.5 inches of rear leg room. The 3-Series has nearly the same exterior dimensions as the ATS, but with a 110.6-inch wheelbase, 42 inches of front leg room, and 36.1 inches of rear leg room, it's extracted more usable space inside.
That said, if you expect to use the back seat for adults and hope to make a good impression, the A4/S4 simply isn't a great pick. With the last redesign, for 2009, the back seat became more usable for adults, but barely that. Most adults will find legroom is limited, and taller passengers will have headroom issues.
With the wagon Avant gone from the lineup, the A4 is just okay on cargo space. The trunk checks in at 12.4 cubic feet, compared to the ATS' teensy 10.2 cubic feet--and the BMW's big 17 cubic feet of room. For more cargo space, the Audi's rear seatbacks fold forward, with a pass-though behind the fold-down armrest for skis.
The A4's built with tight seams and a uniformly high level of fit and finish inside and out, but there's plenty of black plastic on the dash and a few buttons and controls with less than perfect feel. New wood and leather choices and some additional metal trims are as handsome as any Audi's ever offered. Unfortunately, Audi's swapped out the steering-wheel-mounted roller controllers for volume and audio controls for switches. For the most part, the A4 and S4 have good sound damping, though the S4's supercharged V-6 generates more of a less distinctive engine note than its old V-8 ever did.