The S5 cabin is done in mostly dark materials, including the woven headliner and sunshade. Lighter trim highlights the roof panel pull (it slides forward from the rear), gauge nacelles, vents, speaker grilles, and control knobs with piano black centers. The black lacquer also surrounds the primary control area aft of the shifter.

A three-spoke leather-wrapped wheel has hand grips at all the right places and just two controls on each side spoke. However, each side has a thumbwheel that serves multiple functions by scrolling up or down or pressing to click, allowing a majority of system operations to be done without removing a hand from the wheel. Oft-used controls like cruise, signals, flash-to-pass/main beams, and wipe/wash are all on handy stalks.

The wheel adjusts for reach and rake with a single manual release, giving all the advantages, proper driving position, spacing from airbag, instrument view; the only downside is that the wheel position does not adjust automatically with the seat/mirror memory system on cars so equipped. The center armrest also adjusts for height and rake, so it you can use it in cruise mode and slide it out of the way for lots of shifting on winding roads.

Front seats range from very good on the A5 to excellent on the S5; an A5 S-line falls in between and that cabin is available only in black leather. Any A5/S5 seat provides for hours of comfort and wiggle room while maintaining all the lateral support required to explore the car's capabilities. On the S5 the headrests are integral with the backrest and not adjustable, yet the head rest and neck protection are all in the right place and satisfactory for those well past six feet. Thigh extensions in the seat cushions let those tall drivers use more chair than just the area under their pants pockets, and there's plenty of leg room and a good dead pedal.

A fast-slide switch on the front seat backrests eases access to the rear buckets which are nicely sculpted and comfortable for most up to 5-feet, 10-inches tall. A substantial armrest folds down over central storage trays and passengers are catered to with reading lights, two speakers per side, coat hooks, outboard storage pockets, cupholders, and a pair of vents with adjustable temperature control.

To enlarge the cargo area the rear seat folds 60/40 from inside or trunk-located handles, while a pass-thru behind the armrest accommodates long, slender items like skis or fishing rods.

The S5 driver faces white-on-gray gauges, an 8000-rpm tachometer and 200-mph speedometer with smaller temperature and fuel gauges outboard in the two teardrop-shaped pods; in between, a bank of warning lights across the top and information display in the center. This panel shows a variety of data, much of it chosen by the driver using the stalk and wheel controls; even on manual transmission cars it displays the gear selected in white and, if another gear offers the same performance on less gas, an arrow and a number for that gear in green.

To the right, at the same height as the gauges and angled toward the driver, is a well-shaded screen for the MMI (multi-media interface) system that controls many of the car's functions and also shows navigation maps and the rear camera view on cars so optioned. MMI has a central control knob, somewhat like BMW i-Drive and Mercedes COMAND systems, but it has four corner buttons keyed to four choices in the corners of the screen, separate Back/Advance/Return keys, and eight keys around it for direct access to radio, discs, navigation, telephone, car systems, and so forth. It will require a little familiarization but it is quicker and requires less button-clicking frustration than similar systems and does not use any control that requires rotating a knob counterclockwise to increase level as some others have done.

The MMI controller is immediately behind the shifter but not accidentally hit by a resting hand or quick shift. To the left of the lever are the parking brake and Start/Stop buttons, and to the right is the volume knob; this is less than convenient in sixth gear so you'll find the steering wheel control the logical, handy choice.

Below the central screen are a pair of vents, the six-disc changer, and some simple switchgear. At the base of the console are the climate controls, with buttons to select fan speed, temperature, airflow, and seat heat and a small rotary knob to make the adjustments. Full auto mode is available, as is full manual control without any confusion.

The navigation system works as directed; we found it neither class-leading nor class-trailing. Sound from the optional 505-watt, 14-speaker Bang & Olufsen stereo system is most impressive, especially in light of the $850 option tab when the B&O system on a big Audi sedan costs perhaps 10 times that much. However, in the S5, there is always that engine note to enjoy if you tire of recorded fidelity.

Outward visibility is quite good, with relatively narrow pillars and the side posts far enough rearward that they don't interfere with lane-change or close-quarter over the shoulder glances. The rear pillars are generally unnoticed, the rear window usefully large and distortion-free, and the edges of the bodywork not totally lost in the distance.

Night driving is further aided by deep amber illumination that offers the fastest recovery time for your eyes, smoked-lens vanity mirror lamps mounted in the roof, and shaded map lights that light your lap, not your eyes.

Cabin storage includes a shallow bin in the armrest, one center cupholder and a phone-sized bin adjacent, glovebox, and door pockets with beverage stands at the leading edge.

The trunk opening is larger than many two-doors and takes advantage of the trunk lid length to open well out of the way. There are four tie-down rings, a spare underneath, and, at 16.1 cubic feet (for the A5; 12.0 cubic feet for the S5), significantly more volume than a BMW 3 or 6 Series coupe, Jaguar XK coupe, Lexus SC430, Infiniti G37 or Porsche 911.