Performance modifications started with an upgraded engine, which was enhanced by Lotus from the standard Opel 2,969 cc (3.0 L) 24-valve straight-six unit used in the GSi.

The multi-link suspension of the Omega, already praised by the automotive press, was modified by Lotus for better high-speed stability and improved handling dynamics.

To combat the problem of significant camber change at high speed and when fully laden, the self-leveling suspension from the Opel Senator was fitted.

The Lotus engineers would have preferred using rack and pinion steering, but cost and space constraints limited them to the worm-and-roller arrangement.

[3] Because the Lotus Carlton could equal or exceed the performance of many contemporary sports cars from the likes of Ferrari and Porsche while also comfortably carrying four passengers, it generated some controversy among the automotive and general press.

Bob Murray, then editor of Autocar magazine, wrote: "Nobody buying this car could possibly argue he either needs or will be able to use a top whack which is claimed to be around 180 mph", and suggested that Vauxhall should follow the example set by German automakers (who had begun electronically limiting the top speed of their high-performance cars to 155 mph (249 km/h)).

[10] In the following months, a gang of thieves used the car to conduct midnight ram raids, stealing around £20,000 worth of cigarettes and alcohol.

[12][13][14] A campaign by the Daily Mail and the Association of Chief Police Officers was launched to have the Lotus Carlton banned in the UK.

[16] By the end of 2017, all model years of the Lotus Carlton were past the 25-year mark, making them exempt from NHTSA import restrictions.