Opel cars appeared under their own name in the US from 1958 to 1975, when they were sold through Buick dealers as captive imports. The best-selling Opel models in the US were the 1964 to 1972 Opel Kadett, the 1971 to 1975 Opel Manta, and the now-classic 1968 to 1973 Opel GT. (The name "Opel" was also applied from 1976 to 1980 to vehicles manufactured by Isuzu (similar to the "Isuzu I-mark"), but mechanically those were entirely different cars).
The Insignia flagship followed exactly the same initiative as the Astra. Once again the Opel engineers’ main objective was efficiency. Thanks to optimized packaging and lightweight materials they could save up to 175kg on the Insignia Grand Sport compared with its predecessor – much to the benefit of dynamics and fuel consumption. Depending on powertrain and equipment, the current Insignia Sports Tourer even weighs up to 200kg less than the similar model variant from the first generation.
This new category, Group A, featured very stringent homologation requirements. In order to qualify for competition, the competing model needed to be produced at least 25,000 times. Furthermore, the FIA required ten percent of these cars to be a specialty model, with another 500 allowed as “Evolution” models. If the 25,000 car limit had not yet been met, the new model had to attain a production number of at least 5000 units a year.
A rare "Sport" model was produced in 1985 to homologate for the sub 1,300 cc class of Group A for the British Rally Championship. These sport models were white and came with unique vinyl decals, a 13SB engine with twin Weber 40 DCOE carburettors, an optional bespoke camshaft, a replacement rear silencer, and few luxuries. This gave 93 hp and a top speed of 112 mph (180 km/h) with a 0–60 mph time of 8.9 seconds. These are by far the rarest models (500 produced) and thus acquire a high market price if one does become available.
The Corsa C was introduced with a 1.7 L DTI Ecotec turbodiesel engine supplied by Isuzu (Circle L) with 75 hp (55 kW). This was later joined by the 1.7 L DI Ecotec turbodiesel engine also supplied by Isuzu. The 1.7 L DI Ecotec did not include an intercooler and this reduced power to 65 PS (48 kW). From 2003, a new 1.3 L CDTI Ecotec turbodiesel engine was supplied by Fiat (MultiJet) which produced 70 PS (51 kW) and a 1.7 L CDTI Ecotec turbodiesel was supplied by Isuzu which produced 100 PS (74 kW). This new 1.7 L CDTI Ecotec featured a variable geometry turbocharger.