The 325Xi was powered by a 2.5-liter inline-six-cylinder (I-6) engine from 2001 through 2005 This engine produced 184 horsepower (hp) at 6,000 rpm and 175 foot-pounds of torque at 3,500 rpm. In 2006, the 325Xi's engine was upgraded to a 3-liter I-6 engine. This engine produced 215 hp at 6,250 rpm and 185 foot-pounds of torque at 2,750 rpm. From 2001 through 2005, the 325Xi came with a standard five-speed manual transmission and had an optional five-speed automatic. In 2006, this was increased to a standard six-speed manual and an optional six-speed automatic. What made the Xi stand-out was that it came standard with all-wheel-drive.
The 325Xi ranged from 18 to 20 miles per gallon (mpg) in the city and 25 to 28 mpg on the highway, depending on the year and drivetrain options. From 2001 through 2005, all 325Xis had a 16.6-gallon fuel tank. In 2006, the sedan had a 15.9-gallon fuel tank, while the wagon had a 16.1-gallon tank.
The 325Xi sedan had 37.4 to 38.4 inches of front headroom, 41.4 to 41.5 inches of front legroom and 54.4 to 55.4 inches of front shoulder room. There was 37.1 to 37.5 inches of rear headroom, 34.4 to 34.6 inches of rear legroom and 54.2 to 55.1 inches of rear shoulder room. The 325Xi wagon had 37 to 38.5 inches of front headroom, 41.4 inches of front legroom and 54.4 inches of front shoulder room. It also had 37.6 to 38 inches of rear headroom, 34.4 inches of rear legroom and 54.2 inches of rear shoulder room.
From 2001 through 2005, the 325Xi sedan was 176 inches long, 68.5 inches wide and 56.5 inches high, and had a 107.3-inch wheelbase. In 2006, the body style changed. It was 178.2 inches long, 71.5 inches wide and 56.1 inches high, and had a 108.7-inch wheelbase. From 2001 to 2005, 325Xi wagon was 176.3 inches long, 68.5 inches wide and 56.3 inches high, and had a 107.3-inch wheelbase. In 2006, the wagon was 178.2 inches long, 71.5 inches wide and 55.8 inches tall, and it had a 108.7-inch wheelbase.