High performance and economy collide in BMW's 2014-MY 328d xDrive sedan. Equipped with a TwinPower Turbo Diesel, the 328d provides the power (180 hp) and comfort that's expected from the German automaker's nameplate. And it delivers that with fuel-sipping efficiency. I spent more than a week driving the pearl white beauty in the hard urban jungle of Los Angeles' dreaded San Diego (405) Freeway and barely used a quarter of a tank of diesel—a pleasant surprise when it came to refueling.

Yes, I said diesel. The BMW 328d is one of the new-generation diesels that don't announce themselves a block away, offer smooth handling and great highway and city performance, but just sips fuel whether you're zooming at maximum highway speed or are stuck in traffic.

With an officially rated 45 mpg, the BMW 328d is about as modern a sport sedan as you can get.

The fuel savings don't stop there. One of the reasons that my fuel consumption was so low wasn't my use of any eco driving techniques; instead it was the sedan's ECO PRO mode, which I used extensively during my daily commute to and from Bobit Business Media HQ. I thanked the auto gods when I was filling up.

This driving mode can save up to an additional 20 percent in fuel consumption, according to BMW. While the ECO PRO caused a bit of a change from the sedan's normal mode—it was easy to get used to and a big fuel benefit in heavy, stop-and-go rush hour traffic. Regenerative braking and stop-start are other features that help to cut fuel use.

I couldn't pass up giving the Sport mode a whirl. It definitely lives up to its name, with good acceleration and sporty handling and control while retaining BMW's solidness.

The passenger cabin is roomy and the controls are intuitive and easy to use. One change I have particularly liked over the past couple of years is BMW's placement of the infotainment screen at eye-level in the center of the dash. I found using the navigation system much more comfortable and easier for at-a-glance updates without taking my eyes off the road. The steering wheel controls also help to limit distractions.

For me, the most pleasantly surprising feature on the 328d was the trunk. It's spacious and roomy with a flat, square-ish shape that's ideal for luggage or business materials. Inside the cabin, there were plenty of compartments to store electronic and other business gear to keep the space uncluttered.

Here's the bottom line: the BMW 328d is just a pleasure to drive.

Editor's note: View our slideshow, "BMW's 328d xDrive Sedan," for detailed photos of the vehicle. Read our overview of the vehicle appearing in the April issue of Automotive Fleet.