Muscle plus luxury, for $131,000 Time to suspend reality. Suspend the notion that many of us could ever afford to buy this car at $131,000. Suspend the notion that, even if we could, there would be an American Autobahn out there somewhere on which we could hammer it to the hilt -- that being 0-60 miles per hour in 4.6 seconds -- and reach a cruising speed approaching 160 miles per hour. But the reality is that here is a luxury sedan -- and I am talking luxury that surpasses that of your basic million-dollar Manhattan apartment -- that is a flat-out muscle car. I can talk about leather, burnished wood, heated/cooled seats front and rear, legroom for Bill Walton, seats that change shape and grip as your speed and cornering change, and suspension that changes with all of that. But first I need to tell you about the heart of this beast. The 2004 Mercedes-Benz S55 AMG (AMG translated from German to Maine-speak means, ''Make this cah as powahful and fast as a competative lobstah boat") is powered by a V-8 engine that features 24 valves, two ignition coils, and two spark plugs per cylinder. All that is boosted by a high-pressure supercharger that is liquid-intercooled, meaning the air that finally hits the compression chamber is cooled, super-packed, and explosive. But how do you transmit 493 horsepower, and, more critically, 516 lb.-ft. of gear-eating torque, to the rear drive wheels? In many forms. Start with an electronic five-speed transmission. Then add goodies. Leave it alone and it shifts for you, seamlessly, without reaching any scary edges of performance. Click into manual and you can shift up or down with a left or right flick of the stick. Use Optimum and all you need do is hold the shifter left of drive for a second and the car upshifts and downshifts for best performance and engine braking. Go into a driver-selected Comfort mode and the car will start out in second, to save gas and limit takeoff, and use two gears in reverse. It's all about sane driving -- as if that will happen. Toss in AMG SpeedShift, which is purported to be 35 percent faster than manual, and the car almost drives itself. It will automatically downshift in heavy braking, and it won't allow an upshift in the middle of heavy cornering. The last can be a terrifying event, as I experienced with a bad driver in a fast car on a high California mountain road (no guardrails, 2,000-plunge to the right) as he upshifted at apex and lost all traction. And then, of course, there are the manual shifters built into the steering wheel, allowing thumb-clicks left or right to run through the gears. That wheel is also part of a luxurious, ergonomically wonderful interior. From the wheel you control not only shifts, but audio, information, and navigation systems. Besides great leather and fine wood, the car features functionality in the form of a multilayer center console and a fold-down rear center console, both with storage and cup holders. Fourteen-way power front seats with lumbar support and memory -- and heating and cooling systems built in -- provide a luxurious, firm ride. Those front seats have pneumatic torso bolsters that respond to speed and cornering and inflate to grip you when speed and cornering get tough. Sound comes from a 12-speaker Bose system that exhibits liquid depth and granite solidity. Safety features include air bags front and rear with front, side-impact, and head bags. The front bags are weight- and crash-sensitive, meaning they deploy only with the force that the crash and the weight of seat occupants necessitate. Stability is provided by myriad systems that use brakes, throttle, and monitors that watch pitch, yaw, body roll, speed, driver intent, steering angle, and braking to fix the problems. This is a big, luxurious German sedan hat will blow the doors off most American sports cars and should be on any enthusiast's dream list. But then reality intrudes.