The majority of all cars sold with a BMW badge come from the 3-Series class of compacts. These vehicles -- in designs of a four-door sedan, five-door station wagon and two-door coupe or convertible -- set a high standard for performance, handling and agility. Model nomenclature amounts to alphanumeric designations to describe the body style and displacement of an engine. Two in-line-six aluminum-block engines -- measuring to 2.5 liters and 3.0 liters -- power the class, earning 170 hp and 225 hp, respectively. Sedans and wagons with the 2.5-liter engine are labeled 325i for rear-wheel-drive (RWD) and 325xi for all-wheel-drive (AWD); for the 3.0-liter plant, the two sedans are the 330i (RWD) and 330xi (AWD). Coupes and convertibles carry similar designations as 352Ci and 330Ci, each with rear-wheel driveline. All 3-Series cars for 2003 have an in-dash CD player available when combined with the optional DVD-based navigation system. For 325i and 325xi sedans and wagons, a third headrest has been added in center spot of the rear bench, along with armrests for front bucket seats and a rain sensor for automatic headlight controls in a premium package. The 325i and 325xi wagons also show a new moonroof. For coupes and convertibles a tire pressure monitor is now optional. The 330xi sedan also gains spoke alloy wheels with run-flat tires in the optional sport package.