Zender present at the 1989 Frankfurt auto show the Fact 4 Biturbo, a prototype supercar that had parts of its body made of carbon and it was equipped with a V8 engine derived from Audi.
The car was equipped with a 3.6 liter V8 engine from Audi with two turbos, that produced 450 hp, combined with a 5-speed gearbox, giving the car the ability to do the 0-100 km/h in 4.2 seconds, having a top speed of 315 km/h. Unfortunately it never passed to production.
