2013 Mercedes-Benz S65 AMG - front three-quarter view, charcoal gray

Mercedes-Benz sells seven different models of its flagship S-Class sedan in the States. Look past the entry-level S400 Hybrid (base price $93,000) and the standard V8-powered S550 models. The four-door at the pinnacle – squashing the amazing S63 AMG ($140,000) and twelve-cylinder S600 ($160,300) as it steps over them – is the bordering-on-preposterous twin-turbocharged twelve-cylinder S65 AMG seen here.

"Excessive" is an understatement, as the S65 AMG leaves little to want. Tucked up front is a hand-assembled 60-degree 6.0-liter V12, force-fed air by twin blowers to develop 621 horsepower and 738 pound feet of torque. All of the mind-blowing power is sent through a robust five-speed automatic to the rear wheels where it seems utterly unchallenged by the sedan's curb weight of 5,082 pounds – the four-door will bust through the benchmark 60 mph barrier in 4.2 seconds and pull all the way to its electronically limited top speed of 186 mph.

Few will ever have the opportunity to see an S65 AMG in the flesh, let alone spend an hour alone with one, so I leapt on the opportunity. Upgraded from the standard trim, this particular test car was an even scarcer bespoke "Designo" model, with exclusive matte paint, custom shades of soft leather and glossy piano black trim. Pricing, as they say, is available upon request.

Driving Notes
  • Despite its omnipotence, the S65 looks rather low-key and almost indistinguishable from its siblings. Observers will note the "V12 Biturbo" badging on each front quarter panel and the "S65" on the rear decklid. Those with really good eyes will catch the slight difference in the horizontal slats on the S65's front grille (three twin-parallel slats, upgraded from four thick bars). Most all of the other sporty cosmetic enhancements are shared with the S63 AMG.
  • It is impossible to defeat the traction control on the S65 AMG, meaning mile-long burnouts aren't going to happen. While acceleration off the line was dizzying, the real fun happened above 50 mph when the explosive power under the hood spooled to its full potential (it's a treat to watch the traction control light blink at highways speeds). An illegal coast-to-coast run at 150 mph would be joyful and effortless, but I would hate to foot the fuel bill (or pay the fines).
  • Of course, the S65 will never feel as nimble as smaller sedans, but its active suspension was more than competent through every series of curves I tossed it into. There is no getting around two-plus tons of mass, but the aggressive staggered tire package (255/35ZR20 and 275/35ZR20) provided plenty of grip at the limit. The unique twin sliding-caliper brakes fitted over cross-drilled rotors effortlessly bled off the speed with very good pedal feel. It is a very large and comfortable luxury sedan, yet it is still very entertaining to drive - much to my surprise.
  • Those who couldn't care less about the S65's mechanical brilliance will find plenty to soothe their souls inside the cabin, as the opulence of a standard S-Class sedan has been turned up a full revolution on the dial. Supple seat leather is stitched, quilted and perforated (heated and cooled too) and the trim is polished to a mirror-like finish. Passengers in the second row will find leg crossing room, power seats and video entertainment. The cabin smells even better than it looks. I can't wait to see how the next S-Class looks and feels inside.
  • As fabulous as the S65 AMG is, the enthusiast in me still prefers the S63 AMG. Its twin-turbo V8, exhibiting almost no turbo lag, is better suited to our stop-and-go congestion and restrictive speed limits in North America. It is slightly lighter, nearly every bit as luxurious, and it only gives up a tenth of a second in the 60 mph sprint. Plus, I can buy a new C63 AMG with the money I save.