The W5 SG followed the same design patterns and technical specs as its regular stablemate with the only extra having been an overdrive transmission system.
The new gearbox led to a slight increase in power making the SG sportier and a bit more fun to drive. Luxury upholstery and accessories were of course included along a generous rear compartment with plenty of passenger room. Having had a production time of just one year, it is one of the rarest models, having been built in close to 250 units, regular and closed-body versions included.