As you know, Porsche always has a racecar for their street cars (or is it the other way around ;) The Porsche 961 is the racing counterpart of the 959, and raced in the mid eighties.
It was 1986, and the LeMans running of that year would be fought over by the swarm of 956/962 cars. Porsche was bound to win with one of those cars, so they figured why not throw a 4 wheel drive car in to see how it would do. Enter the 961.
Mods from the 959 street car included a bigger, moveable rear stabilizer bar; the radiator was enlarged, the engine was pumped to 640Hp, and the wheels were changed. Also modified were the brakes up to 956 specs. It was entered in the IMSA-GTX class all by itself (the #180 car see here). The plain white non-sponsored 961 paraded itself around the track for hours upon hours without hesitation. It finished 1st place in class and 7th overall, an extraordinary feat.