The 525i becomes the 528i, now with 230 horsepower, while the old 530i becomes the 535i with 300 horsepower.
In fact, the addition of the twin-turbocharged, 300-horsepower six cylinder to the 2008 BMW 535xi Sports Wagon makes it more powerful than the predecessor 540i wagon with 290-horsepower V-8.
BMW also updated the interiors of its early-for-2008 5-Series sedans and wagons and adds an optional Lane Departure Warning system that subtly vibrates the steering wheel when it detects a driver might be wandering out of his or her lane.
With annual sales of more than 50,000 in the United States, the five-passenger 5-Series cars are used both as family and business cars and rank as BMW's second most popular models, after the smaller, lower-priced 3-Series.
For 2008, 5-Series manufacturer's suggested retail prices, including destination charge, start at $45,075 for the base 528i. This is up from the $44,195 starting price for a 2007 525i.
But the 2008 starting price still is midway between major competing luxury sedans such as the 2008 Audi A6, which starts at $43,725, and the 2007 Mercedes-Benz E350, which starts at $51,325.
Buyers of the 5-Series sedan like the image that the BMW badge conveys - of a four-door car that has a performance heritage, a good bit of technology and is anything but stodgy.
But while the 5-Series is a recommended buy of Consumer Reports magazine, it's not among the top vehicles in J.D. Power and Associates' Initial Quality Study that tallies problems in the first three months of ownership. In the 2007 IQS released this month, BMW ranked below average and below lower-priced brands such as Chevrolet and Kia.
It's worth mentioning that BMW owners also receive four years/50,000 miles of free maintenance that includes scheduled oil changes and even replacement of worn windshield wiper blades. This is in addition to a four-year/50,000-mile limited, bumper-to-bumper warranty.
It is easy to notice the newfound power in the 2008 BMWs.
The test 535xi could zoom forward after just a hint of a lag when the gas pedal was slammed down. I found the car moving aggressively to claim openings in traffic and bound up hills, though with a feeling of some heaviness and solidity attached.
The sedan weighs in at nearly 4,000 pounds, which is about the same as a Chevrolet Colorado pickup, so this BMW doesn't feel lightweight or flighty. Peak torque of 300 foot-pounds can come on as low as 1,400 rpm and stay to 5,000 rpm, which is a satisfying range for any kind of driving.
The 3-liter, twin-turbocharged, double overhead cam, inline six-cylinder with variable valve timing for both intake and exhaust functions is the same one put into the BMW 335i and adds a significant 45 horsepower and 80 foot-pounds of torque to the 5-Series beyond the previous engine.
It was mated in the test car to an updated, Steptronic automatic transmission that could be shifted manually, if I wanted, without clutch pedal.
Best of all, for 2008, the Steptronic is a no-cost option on all 5-Series cars, so drivers don't incur a charge to get it instead of a manual transmission. BMW has finally dropped its confounding and difficult-to-operate Sequential Manual Gearbox.
Power is increased - to its highest ever - in the base 5-Series car for 2008. Now called the 528i, it gets a 230-horsepower, 3-liter, double overhead cam, inline six-cylinder with variable valve timing and no turbocharging. Peak torque is 200 foot-pounds at 2,750 rpm.
The top 550i sedan retains its 360-horsepower, 4.8-liter V-8.
Fuel economy isn't a highly touted characteristic of BMWs, but the tester performed within the federal ratings of 17 mpg in city driving and 25 mpg on the highway, even though I didn't try to conserve fuel.
Handling, as expected in a BMW, was exceptional. The car body was well-controlled in all maneuvers, giving the feeling of it hunkering down securely over the wheels even over some busy road surfaces.
I appreciated the bigger door map pockets and better positioning of the window buttons on the door armrests.
The test car had optional, multicontour seats that offer so many adjustment possibilities, it would be tough not to find a comfortable resting position.
THE VEHICLE: 2008 BMW 535xi, a front-engine, all-wheel-drive, five-passenger, midsize, luxury sedan
BASE PRICE: $51,500
DESTINATION CHARGE: $775
PRICE AS TESTED: $61,825
ENGINE: 3-liter, twin-turbo, inline six-cylinder producing 300 horsepower
TRANSMISSION: Six-speed Steptronic automatic
EPA MILEAGE: 17 mpg city, 25 mpg highway
TOP SPEED: 150 mph
LENGTH: 191.1 inches
WHEELBASE: 113.7 inches
CURB WEIGHT: 3,946 pounds
BUILT IN: Germany
OPTIONS: Premium package (leather upholstery, ambient light package, garage door opener), $2,100; navigation system, $1,900; sport package (includes multicontour front seats and sport steering wheel), $1,300; premium hi-fi sound system, $1,200; comfort access with key-free entry and start, $1,000; cold weather package (includes heated front seats and steering wheel), $750; parking sensors, $700; high-definition radio, $500