The 550 is an upgrade of the 545, with a bigger V-8 that churns out 360 horsepower, enough for thrilling acceleration and an EPA-imposed gas-guzzler tax of $1,000.
But once you've shelled out $65,000, the cost of the test car with options, that extra grand is just a blip. Of course, there also is the frequent stops for $3-a-gallon gas, but hey.
The new V-8 is a muscular unit that emits a high-performance growl and packs loads of torque, enough for significant pulling power even in sixth gear.
All the new 5-Series cars, from the base 525i to the frenetic M5, continue with the taut suspension and solid chassis that has made them the leaders among midsize sports sedans. The 550 handles with poise and precision, combining race-car cornering with a ride that is supple and refined.
Also continuing for 2006 is the controversial styling that surfaced in 2004, a look that some find progressive but others see as bulky and awkward. To me, the sedan looks heavy and fussy, deviating from BMW's sleek and sporty designs of the past.
Another item that stirs controversy is BMW's unique iDrive system, a driver interface that works with a central knob to work the audio, climate control, navigation and computer functions. It's annoyingly complex and hard to fathom.
But when all is said and done, it's hard to beat a BMW for the business or pleasure of driving.
Vehicle type: Five-passenger, four-door sedan, rear-wheel drive.
Engine: 4.8-liter V-8, 360 horsepower at 6,300, 360 pound-feet torque at 3,400 rpm.
Transmission: 6-speed manual.
Wheelbase: 113.7 inches.
Overall length: 191.1 inches.
Curb weight: 3,308 pounds.
EPA rating: 16 city, 23 highway.
Highs: Powerful engine, superb drivability, luxury features.
Lows: Awkward iDrive, controversial styling, pricey.