In addition to its West German home market, the Kadett A sold strongly in what were becoming the manufacturer's traditional export strongholds (notably in Benelux, Scandinavia, Austria and Switzerland). Between February 1964 and the Autumn/Fall of 1965 the cars were also exported to the United States where they were sold through approximately 500 Buick dealers. The same 993 cc engine was fitted and it is not clear whether it was differently tuned for North America: horsepower ratings were differently computed in the USA, following locally devised "SAE" rules: for American market purposes the maximum outputs for the engines were quoted as 46 hp (34 kW; 47 PS) and 54 hp (40 kW; 55 PS).
The GSi's engine mapping had been carried out by Opel tuning specialists Irmscher. A model with the 82 PS (60 kW) 1.4 L multi point fuel injected engine, which was otherwise mechanically identical to the GSi, also became available as the Nova SRi in the United Kingdom. In January 1988, a turbocharged version of the Isuzu diesel engine was introduced, with power increased to 67 PS (49 kW).