The V8 and V12 drivetrains are absolutely silky when cruising around. The six-speed automatic is extremely smooth, yet it's among the most responsive we have ever experienced. Hit the accelerator pedal and the transmission drops a gear or two without any of that hesitation found in so many automatics. The additional gearing of the six-speed allows a lower first gear for quicker performance off the line, closer ratios in the middle gears for better mid-range response, and taller top gears for improved fuel economy. Frankly, we found the Steptronic feature superfluous. With a transmission as responsive as this one, manual shifting seems more of a toy than anything else. Just put it in Drive and control the transmission with your right foot.

The 4.8-liter V8 engine is a delight, very smooth when cruising, but ready and willing to play at the edges when asked. Combine the smooth drivetrain with the smooth ride and the 750i feels deceptively slow. This car feels so smooth cruising at 80 to 100 mph that it's almost more comfortable to drive in traffic, as then you can easily see when you're turning into a ticket magnet. For the same reason, you're likely to find yourself coming into corners carrying more speed than you realized, then having to get on the brakes a little harder than originally planned. Unlike in most cars, this isn't a scary thing, though, because the 7 Series almost never loses its composure. Just kind of a "Whoa, Nellie! Slow this baby down." This combination of outstanding dynamics and deceptive travel speeds says something about both the joy and the trepidation in a car as capable as the 7 Series. Put more simply, watch your speed in this car, because you just may find yourself having too much fun.

The same goes for when you're sitting at a stop light, impatient to get on your way. Punch the accelerator and the 750i leaps into action, almost too quickly if you're not paying attention. BMW claims a 0 to 60 mph time for both 750s of just 5.8 seconds. The V8 in the 2006 750i is rated at 360 horsepower, up 35 from the '05, and 360 pound-feet of torque, up 30 from the '05. It earns an EPA-estimated 17/25 mpg City/Highway, giving up 1 mpg from the '05. Its sophisticated Valvetronic system has eliminated the throttle completely, eliminating pumping losses for improved efficiency by letting the valves, which benefit from BMW's double VANOS variable timing, control the airflow through the engine. For 2006, the V8 trades the previous engine's infinitely variable intake system, which optimized power across the engine's rpm range, for a two-stage setup, one of which is tuned to low-to-medium engine speeds, the other to higher rpms. BMW says the larger engine's increased torque lets this less sophisticated system do the same job and as well as last year's more refined system. We're not persuaded, as the acceleration on the 2006 750i was not as linear as on previous models, with a perceptible transition between the two intake stages. It still scoots, but just not as silky as before.

If pure silk is what you want, try the V12. The 760Li was launched as a 2003 model with a 6.0-liter, V12 engine that shares its basic architecture and most of its technology with the V8. For 2004, BMW introduced the sportier 760i with the shorter wheelbase to the North American market. The V12 engine added an innovation of its own: direct fuel injection, which delivers fuel directly into the cylinders, rather than to intake ports on the cylinder head. This improves power and reduces emissions. The V12 generates 438 horsepower and an impressive 444 pound-feet of torque. The V12 is turbine smooth, and whisks the sumptuously luxurious 760i from 0 to 60 mph in just 5.4 seconds, while earning an EPA estimate of 15/22 mpg City/Highway.

The 7 Series can stop in a big hurry when necessary. Massive, ventilated disc brakes, among the largest and most powerful BMW has ever used, are fitted with aluminum calipers at all four corners. Electronic brake proportioning ensures that the meaty tires are making best use of all available braking traction by transferring braking force to the tires with the best grip. Dynamic Brake Control reinforces the driver's pedal effort in emergency braking to help the car stop in the shortest possible stopping distance, even if the driver mistakenly relaxes pressure on the brake pedal. The underlying electronics, however, are less than ideal, at times keeping the brakes applied longer than we wished as we rolled to a stop at an intersection. The Automatic Hold feature worked as promised, however, holding the car at a stop on a slope until the driver presses on the accelerator pedal, and setting the parking brake when the car is turned off. The feature can be switched on or off using the iDrive menus.

Summary

The BMW 7 Series is so smooth that full days behind the wheel are not taxing, and it's very comfortable in heavy commuter traffic. It's easy to drive this car well, even on winding mountain roads, and few luxury sedans can keep up with it at high speeds. The interior is sumptuous. And these cars are stuffed with the latest technology. Dynamically, this may be the best car in the class. That's no small feat, given that the competition includes some of the best, most expensive cars in the world. But some of the technology sometimes seems to be more of a distraction than an aid.