Built to replace the 75 and based on the parent Fiat Group's Tipo platform, the 155 was somewhat larger in dimension than the 75 but evolved its styling from that of its predecessor. The 155 was designed by Italian design house I.D.E.A. An exceptional drag coefficient of 0.29 was achieved with the body design. The single most significant technical change from the 75 was the change to a front-wheel drive layout.