The Allanté was available in two body styles for 1990. The Allanté convertible hardtop included both a convertible top and a removable all-aluminum hardtop. The new convertible was offered as a convertible only and did not include the hardtop. The standard and optional content of the two models was identical with the following exceptions: an analog instrument cluster was standard on the convertible and a no-cost option on the convertible hardtop. The digital instrument cluster standard on the convertible hardtop was an extra cost feature for the convertible. A pearl white exterior color was available at no charge on the convertible hardtop and an extra-cost option for the convertible.

The only exterior change for 1990 was the addition of a new beige metallic color. This provided a total of eight color choices for the Allanté. A new natural beige durosoft leather color was also offered. Other revised or new items for 1990 included a standard S.I.R. driver-side system, a smaller steering wheel with a thicker rim cross-section, new standard Delco-Bose compact digital disc player and an improved cellular telephone option. A Traction Control system providing increased steering ability and improved stability when accelerating as well as increased traction on slippery surfaces was standard.

New chassis calibration involving revised strut valving and the use of gas-charges struts. A new direct-acting front stabilizer shaft was also used. Shift points for the Allanté's transmission were changed to 40 and 60 mph from 1989's 25 and 60 mph.