A number of sport sedans offer base engines that accelerate enough but fall short of the effortless passing power expected of a luxury car. Such is the case with the C300. Encumbered by an extra 210 pounds versus rear-drive models, our test car's 228-horsepower V-6 moved out with adequate thrust. Pushed hard, the seven-speed automatic dispenses quick upshifts, and the engine emits a satisfying exhaust growl as the tach needle swings right.

The drivetrain's two driver-selectable modes, Comfort and Sport, alter accelerator sensitivity and automatic transmission shift patterns. Even in its Sport mode, the transmission isn't eager to kick down, so passing power is modest. But the engine offers good balance: I loaded up enough weight to simulate three adult passengers plus baggage, and the C300 didn't strain. The BMW 328i and Lexus IS 250 deliver peakier power with lackluster oomph starting out. (As base engines go, the Audi A4's turbo four-cylinder has the group beat.)

Several editors observed some accelerator lag, even in Sport mode. I noticed some, but it's not as pronounced as in some Mercedes with the automaker's 5.5-liter V-8. That king-sized V-8 makes up for the lag with effortless power, however; the C300's V-6 … not so much.

Stepping up to the C350 gets you a 268-hp, 3.5-liter V-6, while the C63 AMG has a 451-hp V-8. A performance package with revised engine calibrations bumps that up to 481 hp. Both the V-8 and 3.5-liter V-6 pack a stronger punch — Mercedes says the C63 can hit 60 mph in just over 4 seconds — but neither will be easy to come by. Of the thousands of C-Class sedans in Cars.com's national new-car inventory, just 5 percent are C350s or C63s. Both cars come with automatics; the C300 Sport also offers a six-speed manual.