The US-built Z4 replaces the Z3 in BMWs lineup. The Z4 is longer and wider. Z4 is available with either a 184-hp 2.5-liter inline 6 or a 225-hp 3.0-liter inline 6. A six-speed manual is available in the 3.0 model. Pricing starts in the $35000-$40000 range.