A brawny new V6 engine and sharp sports package make the E-Class more engaging.(News)

Byline: GREG KABLE

We don't recall thinking the two-year-old Mercedes-Benz E320 was falling off the pace in any way, but clearly the decision-makers in Stuttgart are a hard bunch to please. They just axed the popular E320, with its three-valve-per-cylinder 3.2-liter V6, replacing it with a new E350 model running a more advanced four-valve-per-cylinder 3.5-liter V6.

First seen in the SLK350 and recently added to the CLS350, the aluminum-block 3.5-liter engine uses a two-stage inlet and continually adjustable intake and exhaust camshafts to dish up 272 hp and 258 lb-ft of torque, compared to the E320's 221 hp and 232 lb-ft. Crucially, the new model's power- to-weight ratio improves, which helps slice nearly a second from the car's 0-to-60-mph time, while lowering fuel consumption by 1.5 mpg in city driving and slightly reducing tailpipe emissions.

But the on-paper improvements, impressive as they are, pale next to the gain in response you experience from behind the wheel. Drive the E350 and you'll soon question whether the more expensive 5.0-liter V8-powered E500 is still a pertinent buy. In real-world driving, little separates the two. The E350 goes about its business in a highly efficient and seemingly effortless manner, without ever becoming too vocal or annoyingly harsh. There are no discernable peaks or troughs in the power delivery. Once you've tapped ...