In 1994 a 167 hp 2.5 L V6 was introduced, thus creating what many considered to be the finest Calibra to date. Available with both manual and automatic transmissions, the V6 wasn’t as fast as the Turbo, but was rather more civilised, and proved to be more reliable than the complex four-wheel drive model with its notorious transfer box issues. 1995 saw the introduction of the the X20XEV Ecotec engine, a cheaper, less reliable derivative of the classic X20XE 16-valve or "red top" engine. This marked a reduction in power from 156 bhp to 136 bhp for the 16-valve version, although the Turbo continued with the C20LET.
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).