We are testing the X4 with the 225 kilowatt xDrive35i gasoline engine.
Like the X3, the X4 has a 3-liter inline six-cylinder engine that yields a peak torque of 400 Newton meters. Both the X3 and X4 have eight-speed automatic transmissions.
BMW says each has a combined city and highway fuel consumption of 8-point-3 liters per hundred kilometers. When it comes to sprinting from zero to 100, the coupé is zero point one seconds faster than the X3. And the X4's top speed is two kilometers an hour higher.
So in technical terms, the X3 and X4 are closely related. But while the X3, which debuted in 2003, has the typical boxy shape of an SUV, the X4, introduced in 2014, embodies BMW's new design concept: that of the sports activity coupé. The roof's highest point is above the driver, then it slopes gently lower to the back.
The X3 with its classical SUV profile has the bigger trunk -- with 50 more liters of capacity, or 200 more with the rear seats folded.
All X4 models are fitted with the intelligent xDrive all-wheel-drive system and Performance Control as standard equipment. Performance Control adjusts power distribution between the left and right rear wheels. That helps improve traction and steering. Handling is lighter and more precise.
While the starting price of the X3 is 38 thousand Euros in Germany, the entry-level X4 -- which does have a more powerful engine -- costs close to 46 and a half thousand Euros.