I'm very sure that this is the car that won the 1998 Nurburgring 24 Hours outright and allegedly could run for around 2 1/2-3 Hours in between fuel stops (Hans Stuck mentioned it in an interview quite a few years ago) thanks to it's Diesel-Fuel burning engine... Voted.
Fun fact... Andreas Bovensiepen is the son of Burkard Bovensiepen, founder of Alpina Burkard Bovensiepen Gmbh... a.k.a. ALPINA. I think he runs the company these days.