We were obliged to park the mega-Bimmer in a multilevel municipal parking deck, which was designed for cars about the size of the 750Li's ashtray. No matter. The car was equipped with BMW's new Integral Active Steering -- four-wheel steering, in other words. With a maximum rear-wheel deflection of 3 degrees, the system reduces the car's turning circle almost 2 1/2 feet. With a full crank on the wheel, this huge car seems to shrink to the size of a pensioner's Lada. It's enough to make der grossen Kopf vom Karl Marx crack a smile. The fifth-generation BMW 750Li is a seriously large car, 17 feet long and well over 2 tons, not to mention the staggering avoirdupois of its ambition. So it's surprising -- even a little scary -- to feel this road-going ocean liner caper through the Eastern highlands like a stripped-down sport coupe. It's the same feeling you get watching a bear ride a bicycle, or Jackie Gleason glide around a pool table, or Warren Sapp sashay across the floor on 'Dancing With the Stars': It just ain't natural. But, of course, nature is what big BMWs must rise above (specifically the physics of mass, inertia and momentum). How do you make a personal limousine loaded with wood, leather, LCDs and circuitry handle like the ultimate driving machine? The new 7 Series, which had its North American debut at Los Angeles Auto Show, has answers for that. Some are predictable and foundational. The metalworking of the body and chassis is astonishing: lightweight high-strength steel where it needs to be, and everywhere else a complex filigree of aluminum and magnesium. Among the all-alloy components: suspension and subframes, coil springs, engine block and final drive. All told, the new 7 Series -- the biggest car in its class -- is 121 pounds lighter than the previous model. To motivate what mass there is, BMW offers three twin-turbo engines: an inline six in the 740i (326 horsepower); a 4.4-liter V8 in the 750i and 750Li (407 hp); and a diesel in the 730d (245 hp and a tractorlike 540 pound-feet of torque at a mere 1,750 rpm). The U.S.-bound models will initially get only the 4.4-liter gas engine. BMW execs won't commit to bringing the oil-burner stateside. And, yet, lighter is not light. The standard-wheelbase 750i weighs a bridge-bending 4,564 pounds. The long wheelbase 750Li is 4,640 pounds. To counter the sway, the lurch and slide of a heavy sedan driven in anger, BMW has completely re-engineered the 7 Series' greasy bits. The front suspension is now a double-arm design, while the rear is an 'Integral-V' design. Meanwhile, there's a phalanx of 'Dynamic' systems -- active dampers, stability control, traction and antilock control, smart brakes -- as well as BMW's uncanny Dynamic Drive body-control system. This last system, one of the car's few options, comprises an electromechanical antiroll bar in the back that nulls body roll as the car corners. So it is that BMW engineering geeks have subverted Newton's laws. But there's still the problem of changing direction. A big, heavy car, relying on those two tires up front, can only exert so much steering force. The heavier the car, the less willingly it will go left or right, right? The 'zolution,' as German engineers say, is the optional Integral Active Steering. Rear steering has been tried by many companies many times and abandoned because of weight, cost and complication. None of that is a factor in the flagship BMW. The effect of all these components -- harmonized by a high-speed data system BMW calls FlexRay -- is pretty amazing. Come to a corner in the 750Li and get on the brakes hard. The dampers instantly react to compensate for the nose-diving weight transfer. Turn the wheel, and the four-wheel steering bites. The car tracks like a phonograph needle. Mid-corner, where other big cars would be fighting desperately against their own body roll, the Bimmer's body stays flat. The six-speed transmission holds its gear so as not to upset the car's balance. Get back on the gas and unwind the wheel. Perfection. In other respects, this is the same car as the previous 7 Series, only drawn with a finer pen. The body styling is leaner and more elegant, and the cabin greenhouse -- the glassy parts -- has moved back on the fuselage for a more aggressive look. The cabin is a beautiful collage of glossy hardwoods, polished alloy and leather. The gear selector has been moved off the steering column to the center console. The dash is dominated by a large, bright 11-inch LCD display for navigation and other functions. Like the 3 Series reviewed earlier, the 7 Series enjoys a new and infinitely better iDrive system, with voice recognition. Among other tech features: rear and side cameras, lane-change and lane-departure warnings and thermal imaging night vision with what BMW calls 'detection of individual persons.' The list of luxuries and trickeries will addle the brains of BMW salesmen. Simply, the car's got one of everything. But what will sell this car is not the giant trunk, the great stereo, the deafening quiet at 150 mph. It's the handling. The assurance, the predictability, the fine-grained tactility coming through the seat and steering wheel, the sheer crazy agility of this thing clearly establishes the BMW as the best-handling big sedan in the world. Maybe not Marx, but definitely a manifesto. E-mail Dan Neil at [email protected].