BMW's two-seat roadster, produced at a BMW plant in South Carolina, transforms for 2003 into an upgraded second-generation design featuring a racy exterior, larger engines and more equipment aboard. Even the name grows -- from Z3 to Z4. The package size expands due to a longer wheelbase and broader track which forge a larger vehicle with more room in the cockpit. Two engines enrich the new roadster. Z4 2.5i gets the BMW 2.5-liter in-line-six tuned to 184 hp with transmission choices of a five-speed manual or Steptronic five-speed automatic. Z4 3.0i brings a 3.0-liter six worth 225 hp and either a six-speed manual or the Steptronic automatic. Later in the year, BMW's sequential manual shifter will also be available. Suspension upgrades for Z4 come out of 3-Series cars with modifications plus a new trapezoidal-link arrangement at the rear, with DSC stability control on hand as well as run-flat tires. The convertible's soft top with optional power controls contains a glass rear window and heat element plus a tight tonneau cover.