Power (and money) have a lot to do with choosing among the new Mercedes S-Class models. The S550 comes with a 5.5-liter engine that has 80 horsepower more it did with the old 5.0-liter 3-valve V8, and it can sprint from 0-60 in 5.5 seconds. The 5.5-liter biturbo V12, lifted from the Maybach and bumped to 510 horsepower and 610 foot-pounds of torque, will do the sprint in a staggering 4.5 seconds. And, remember, this is a huge, heavy, fully equipped luxury car.

Both transmissions upshift and downshift with the speed of a lightning bolt, with no hesitation whatever, regardless of shift mode. The transmission is designed to upshift at redline to protect the engine.

The Airmatic air suspension system has been retuned to give a far sportier and yet flatter ride than the previous S-Class could offer. The Adaptive Damping System shock absorbers and the steering effort and feel have also been retuned toward the sporty end of the spectrum with no dartiness, just a nice, progressive feel. The Automatic Body Control active suspension option cuts body roll at a rate 60-percent higher than the first version, and you can really feel it working when you throw the car into a fast, sweeping downhill curve like those we experienced on our Swiss-Italian test drive.

The new Brake Assist Plus brakes are, in a word, spectacular in their stopping power and stopping distance performance. With the new system, the brake lights go to full brightness and pulsate in the event of a panic or ABS stop.

We solved all of the mysteries of a brand-new car with a completely new switch layout and control system without looking in the owner's manual. It's that easy to go from one of last year's models to the 2007 S-Class, and we think that counts for a lot for the older portion of Mercedes-Benz's clientele with this car. It may be inordinately quick and fast on its feet for a big luxury car, but it's also easy to use and easy to learn.

It's also quiet. Mercedes-Benz says they spent an inordinate amount of time and money using human volunteers on the quiet aspects of the car, and called in some of the experts from the Maybach ultra-luxury car team. There are 170 individual pieces of sound and noise control equipment in the new car, including a patented front floor panel that cuts both noise and vibration. At continuous cruising speeds up to 125 mph, the S-Class is very, very quiet.