Restyling in 1991 brought a series of aesthetic and technical upgrades to the Spyder. The most significant modification regarded the introduction of four-valve-per-cylinder heads with four overhead camshafts, which served to increase performance despite the fitting of a catalytic converter required for certain markets. From a styling point of view, the car was reworked with new, slimmer headlights, taller bumpers and sills, 16-inch six-spoke alloy wheels, more aerodynamic rear-view mirrors, and a distinctive spoiler at the base of the windscreen invented by world-renowned stylist Marcello Gandini.