BMW’s X4 is a coupe-like variant of the more traditional X3 crossover. Some people love the racier look, but others lament the tighter cargo area. Under the hood, the X4 comes standard with a four-cylinder engine producing 248 horsepower. An inline six-cylinder engine is also available, with either 382 horsepower or 503 horsepower depending on the model. Unlike the X3, however, the X4 cannot be had with a plug-in hybrid powertrain.