On the 1992 Geneva Auto Show, Lamborghini presented a prototype of an open-top version of their flagship, the Diablo Roadster, naturally the roof was removed and the chassis was altered to cope with this, but there were also some other changes which would make their way to the Diablo and Diablo VT production model.
Like the exterior rear view mirrors, which were now finished in the same color as the bodywork, but a more evident change was the dashboard, reduced in size but still holding all the necessary elements. The engine lid was also redesigned, now with a 'tunnel' between the two seats to allow the rear view mirror, which was placed on top of the windshield, to pass between these seats. The body part behind the engine hood now used a grill to get rid of the heat generated by the exhaust system underneath it, and also because the air extractors in the engine hood became smaller.
The two air intakes on top of the rear wings were larger, to allow a greater air flow into the engine compartment, and the two air ducts on the side of the car also became bigger, and were also to be used on the VT version.
Production of this exclusive vehicle was intended to be limited at one time, but unfortunately it never reached the production stage.
Some customers really wanted an open Diablo so Walter Koenig, from Germany converted a few Diablo Coupe's into Roadsters, designed similar to the Prototype Lamborghini presented. Koenig could also mount a different front and rear spoiler (check out the Koenig Diablo), and tuned the engine to obtain a power output of about 750 Bhp by adding two turbo's on the engine. Koenig also built some targa styled Diablo in those years, they were the same price at US $ 250,000, but lacked the design of the original Diablo Roadster prototype's low front windscreen, according to several sources about five Roadster replica's were made, three of them including the special Koenig bodywork, two with standard Diablo bodywork.
Koenig actually contacted OZ-wheels to obtain the correct Lamborghini wheels design but enlarged to 18-inch, but a contract between OZ and Automobili Lamborghini SpA didn't allow OZ to make this specific wheel design for anyone else, so Koenig had to use the standard 17-inch with the central wheel crest repainted in the cars main exterior color.
In 1995 Koenig was stopped by the Lamborghini Factory, simply because the official Diablo Roadster was offered for sale to the public, directly from Sant'Agata, so it was understandable the demand for Koenig replicas didn't last long after this.