Endowed with 202 horsepower and 191 pounds-feet of torque, the 2.5L accelerates from zero to 60 mph in roughly 7.5 seconds. It's a decent clip, but it feels poky sometimes because the car's suspension can harness much more. The 3 Series no longer includes an engine this modestly powered.

The ATS 2.0L makes 272 hp and 260 pounds-feet of torque, and it feels similar to BMW's turbo four: plenty of low-rev torque and quick sprints. When equipped with rear-wheel drive, the 2.0L hits 60 mph in 5.7 seconds with the automatic and 5.8 seconds with the manual, according to Cadillac.

The 3.6L's V-6 generates 321 hp but only 275 pounds-feet of torque, so it didn't feel much quicker than the 2.0L in normal driving. The 2.0L's turbo engine hits its torque peak around 1,700 rpm and stays there through 5,500 rpm, while the 3.6L's V-6 peaks closer to 5,000 rpm — in a car with a 7,200-rpm redline. Only when it was truly wound out did the V-6 earn its keep. Cadillac estimates its zero-to-60 time at 5.4 seconds.

If the acceleration estimates are correct, the ATS' more powerful variants essentially match the 328i and 335i sedans, even though the ATS has horsepower and weight advantages over comparable automatic BMWs: The 2.0L has 32 more hp and is 88 pounds lighter than the 328i, and the 3.6L has 21 more hp and is 133 pounds lighter than the 335i. However, the 3 Series' eight-speed transmission is an advantage in its own right.

As of this writing, only the base ATS 2.5L has EPA-certified mileage ratings: 22/33 mpg city/highway. Cadillac estimates 22/32 mpg for the 2.0L and 19/28 mpg for the 3.6L. BMW's EPA-certified ratings are 23/33 mpg for both the 328i and the 335i. (All mileage specs cited are for automatic, rear-drive versions.) Another advantage for Cadillac is that the 2.5L and 3.6L use regular gas. The 2.0L prefers premium for full output but can also run on regular, Cadillac says.

The ATS' standard transmission is a no-nonsense unit with automatic Touring, Sport and Snow modes. You can shift manually by moving the gloriously conventional gear selector to the left and then pushing it forward and back. (Magnesium steering-wheel shift paddles come only on the Performance and Premium trim levels.) The transmission is more responsive than the CTS' automatic, which I've criticized for excessive lag. It upshifts smoothly and doesn't dally when you call for passing power.

Although I love manual transmissions, I'm lukewarm on the execution with the 2.0L. When you hit the clutch and let off the gas to upshift, the engine speed drops so lazily that it's not rev-matched enough when you let the clutch back out. The transmission bucks back as a result in the lower gears. I also found it too easy to catch the Reverse gate, which is to the left, when going for 1st or 2nd gear. You can rev-match better on the downshift because the accelerator doesn't exhibit too much lag, especially when Sport mode is engaged, as it makes the throttle more sensitive.

The ATS does a pretty good job of damping out engine sounds — always a concern with the capable but raucous Ecotec engine family. BMW's turbo four sounds faintly diesel at idle but improves with speed. Of the three ATS engines I drove, the sound of the 3.6 stood out to me — not in a positive way. I quickly tired of the engine's droning sound when cruising on the highway. Otherwise, the ATS' cabin is admirably quiet, with the main source of noise being the tires, plus the occasional wisp of wind noise.