BMW's top-selling model enters its fifth generation with significantly altered exterior design and a new chassis underneath. In common BMW fashion, the 325i and 330i sedans have been introduced first and are now in showrooms. 3 Series wagons will arrive later, likely followed by coupes and convertibles. The new model is filled with technical advances. Among the most notable, the Dynamic Stability Control system is improved. In the 325i, BMW's 3.0-liter six-cylinder engine now produces 215 horsepower. Stepping up a notch, the 330i gets a 255 horsepower version㬚 more than in the 2005 330i. With a history dating from 1977, the 3 Series has come to represent driving excellence for several generations of enthusiasts.