The R129 was offered as a two-door roadster with an automated (electro-hydraulic) fabric convertible top adorned with a color-coordinated automated headliner and a manually removable hardtop that could be fitted over the stowed convertible top.

The R129 was based on the shortened underbody of the Mercedes-Benz W124[2] and featured many innovative details for the time, such as electronically controlled damping (Adaptive Damping System ADS, optional) and a hidden, automatically extending roll bar. The slightly outdated rear suspension of the R107 predecessor was replaced by a modern multi-link axle. Standard features were plentiful, with power windows, mirrors, seats and a hydraulic sunroof.

This car has the distinction of being the first passenger vehicle to have seat belts built into the seats instead of being attached to the floor, B-pillar and transmission.

Diana, Princess of Wales, sold her Jaguar XJS for a metallic red 500SL, becoming the first member of the royal family to use a foreign car.