There's lots of performance in the Audi A8's aluminum-framed body, but passengers don't lose out to cubic inches or g forces. It's the opposite, in fact, particularly with the long-wheelbase car. Both A8 body styles can be counted among some of the best long-distance cruisers available today, thanks to ample space, multi-adjustable seats, and some thoughtful touches that rise above some of the busy lines of the cockpit.
You can have the A8 in either standard- or long-wheelbase form (117.8 and 122.9 inches between the wheels, respectively), with some clarification. The S8 sport sedan is short-wheelbase only; the W12 is long-wheelbase only. Where you have a choice in footprints, we'd recommend you choose the A8 L. That extra five inches goes almost entirely to rear-seat leg room, and though it makes for longer rear doors and slightly less nimble road manners, neither are major enough to cause acid reflux or assorted agita.
No matter which model, the A8 provides lovely, supportive, 18-way adjustable front seats that combine soft-touch cushions with firm understructure for excellent support during very long-distance drives--think 600, 700, 800 miles. Mid-back support is excellent, and Audi's headrests don't force the driver's head too far forward. An option for 22-way comfort front seats bring in ventilation and massage functions. Audi's seat-control interface works inventively: a wheel on the side of the seat is orbited by a lever. Flick the lever and it brings up a screen menu that displays which cushions you're inflating or deflating. No bladder mysteries here.
The standard-issue back seat offers swell support for lanky passengers, but there's not enough leg room. The A8 L is the way to go, and not just because it piles on exotica like multi-mode climate control, power rear seats, an extending footrest and a massaging seat function. With either body, we'd buy the panoramic glass roof that opens up the cabin to a flood of light without trimming head room much.
The A8 doesn't do well in other measures. The 13.2-cubic-foot trunk is small. The cabin is quiet and refined, but more sporting models generate a fair amount of tire noise.