BMWs have long set the standard for sports sedans, and while a handful of competitors have encroached on their territory, the 5-series sedan, and the 535i in particular, is one of the benchmarks against which others in this class are judged.

Over the course of a couple of months, I drove both the 528i and the 535i. Which car is best for you depends on a number of factors, including how much you want to spend. The 528i, with a 230-horsepower engine, has a base price of $44,300. The twin-turbo, 300-horsepower 535i starts at $49,400. A sport station wagon is also sold.

This review will focus on the 535i.

The 5-series is no longer alone at the top of its class. It has serious competition from the new Cadillac CTS and the Infiniti M-class.

The 535i's engine weighs 150 pounds less than a 4.0-liter V-8, yet it makes equal power.

The silky smooth power of the new twin-turbo six-cylinder is an enthusiast's delight. This is BMW's first production twin-turbo engine. It has direct fuel injection and an all-aluminum crankcase. Noise and vibration are minimal because an inline engine is inherently smooth.

In the old days, turbocharged engines felt lethargic at low rpm and then they exploded with power as the turbo kicked in. Those days are gone. The 535i's engine is fitted with two small turbos, one for each set of three cylinders. Small turbos spool up faster, minimizing turbo lag. Because these turbos are mounted near the exhaust manifolds, they are made of heat-resistant material for greater efficiency.

On the road, the 535i never gives a clue that it's turbocharged because the engine delivers its power in a linear fashion. Pulling onto the freeway or passing on two-lane roads is a breeze because punching the throttle results in a quick blast of speed that will push you past the speed limit in a flash.

The six-speed automatic now shifts quicker, and paddles on the steering wheel can be used for manual shifts. A six-speed manual is also available.

Great handling is mandatory for BMW, and the 535i sticks to the road with delightful balance. The test car was equipped with the sport package that consists of 18-inch wheels, performance tires, special front bucket seats, active roll stabilization and a stiffer suspension.

The suspension absorbed bumps easily, yet it is firm enough to counteract body lean in turns and keep the car from feeling light at high speeds. The 535i feels so solid and composed on the highway that it's obvious that the car was developed in a country where high-speed driving is a matter of national pride.

BMW brakes are among the best around, and the 535i stops with authority. Anti-lock, traction control and stability control are all standard equipment.

Inside, the 535i uses BMW's iDrive system for controlling many of the car's functions. This system can be tremendously frustrating because even simple tasks are often complicated, but BMW continues to refine the menus and make operation easier. Separate controls give quick access to the radio and climate control.

The deeply contoured front bucket seats are among the best around. The under-thigh support is outstanding as well as adjustable. The back seat is big enough for adults to ride comfortably.

High-tech options include Active Steering, Active Cruise Control and Park Distance Control. Other items that make an appearance on the 2008 models include a lane departure warning system that notifies the driver of an inadvertent lane change by vibrating the steering wheel.

Active Cruise Control now includes a stop-and-go feature that enables the system to function in heavy traffic.

Price The base price of the test car was $49,400. Options included leather upholstery, the sport package, park distance control, navigation system, HD radio and a premium audio unit. The sticker price was $61,125.

Warranty Four years or 50,000 miles.