The BMW X4 is a compact luxury crossover that was first introduced in 2014. It is based on the BMW X3 and was designed to stand out from its more traditional-looking sibling. The X4 has a more dynamic, coupe-like styling than the X3 with a sloping roofline and a more aggressive-looking front fascia. It is available in a variety of trims, including the xDrive20i, xDrive30i, xDrive30d, and the M40i.