This sport-luxury crossover has a lot of competition, but the X3 fares especially well when it comes to horsepower and performance from its 6-liter engine in either turbocharged or naturally aspirated form. BMW's EfficientDynamics technologies boost the X3's mileage to 19 mpg in the city and 26 mpg on the highway. The X3's starting price is still well under $40,000.
