The backdrop is New York’s Hudson Valley, but I’m flying autobahn-style in the Mercedes S65 AMG, the world’s fastest four-door. A $195,000 version of Mercedes’ flagship sedan (Read “Behind the Line: Mercedes-Benz S-Class”), the S65 features a hand-built, twin-turbocharged V-12 engine capable of putting out 604 horsepower. And it has something equally indulgent and high-tech as well: its seats.

Mercedes’ Drive Dynamic seats are perhaps the industry’s most advanced: adjustable in myriad ways—including massage settings—and capable even of launching preemptive safety measures before a collision. But the Drive Dynamic seats are hardly anomalous; they are a leather-bound testament to the growing emphasis on interior and seat design in automobiles as carmakers look for every edge in a brutally competitive market. Luxury brands in particular have been adding everything from gimmicky gizmos to plush finishes to advanced safety features.

A car owner “spends the majority of time inside the vehicle,” says Lars Galley, of DaimlerChrysler’s customer research department. “Compared with the exterior styling, the interior has more time to make an impression on the driver.”

The new BMW 3-Series convertible delivers a technological first: seats, armrests, and a shift knob infused with reflective polymers that can reduce the leather’s surface temperature by as much as 36 degrees. Say goodbye to flash-fried thighs on sunny top-down days. And today’s techno-laden Lexus LS 460L and its hybrid sister sedan, the LS 600hL, offer a rear seat with airliner-grade reclining, along with a motorized footrest and shiatsu massage.

And there’s that Benz. Its Teutonic thrones have 15 separate pneumatic chambers that allow me to precisely tailor the amount of support from my thighs to my shoulders. Four levels of massage—slow-and-vigorous is my favorite—are designed to soothe muscles and fight fatigue. Linked to the stability control system, which monitors g-forces to prevent skids and rollovers, the seats can be programmed to grip your body more tightly through fast corners. (That function proves more distracting than helpful, especially at triple-digit speeds). Naturally, a flick of a switch turns the seats toasty-warm or frosty-cool.

Mercedes’ seats aren’t about just soothing your behind, they may possibly save your neck. They’re linked to a collision-avoidance system that uses radar to monitor traffic and springs into action when it senses the driver can’t stop in time to avoid a crash. In the moments before impact, seat belts tighten. Front passenger and rear seats shift to optimal crash positions. Seat bolsters inflate to hold occupants in place and boost the performance of seat-mounted side airbags.

It’s practically sci-fi stuff, especially when you consider that most cars sold in the U.S. didn’t even offer standard front seat belts until the mid-1960s. Volvo created the first modern, three-point seat belt on its PV 544 sedan for 1959. Then, with the science of ergonomics in its infancy, Volvo began working with medical experts to develop more-spine-friendly seats. Modern drivers might offer a two-aspirin toast to the 1964 Volvo Amazon, which pioneered the world’s first adjustable lumbar support (though you needed a screwdriver to operate it).