A flash of grey in the history book of legends. In 1982 the FIA decided to introduce a new category of racing machine called "Group C". This new breed of racing car was designed as a replacement for the Group 5 and 6 prototypes, which as far as racing cars go, were absolutely bonkers. Group C then was a further advancement on the technologies learned from previous prototype racing, with more powerful engines, lighter chassis's and more downforce. If the Group 5 and 6 prototypes were for nut-jobs, then Group C was designed for the mentally unhinged: Men with vegetables so large they can't sit down properly. Yeah, that big. The Group C field included cars like the Porsche 956, the Jaguar XJR-8/9 and arguably the most legendary of them all, the Mazda 787B. These are names that will live on in motorsports' pages of history forever, however, there was one car that perhaps didn't receive the recognition it deserved: The Sauber-Mercedes C9. It competed in the 24 Hours of Le Mans only three times, from 1987 to 1989. Its final year of Le Mans proved to be it's most successful year as their three-car entry all finished the race and placed first, second and fifth in a very strong field. The C9 is also one of the fastest cars to ever grace the hallowed tarmac of Le Mans, where in it's winning year, it reached a top speed of 400 kph (248 mph) during qualification. The Italian developers Kunos Simulazioni have recognised this cars' true greatness by creating a stunning replication in the Assetto Corsa simulator. There are very few cars in SimRacing that are genuinely frightening to drive. Make no mistake, the Sauber-Mercedes C9 is at the pointy end of that list. It has a 5.0 Litre turbocharged V8 that is capable of producing in excess of 750bhp and 500Nm of torque. All of this being sent to the rear wheels of a car that weighs less than 1000kg, means that the power delivery and general performance is dramatic. The real car produced a massive amount of downforce thanks to the ground-effect and it's massive rear diffuser, meaning that it simply devoured high speed corners. The virtual version is a replica of the low-drag Le Mans-spec version, which still produced monumental quantities of accelerated gravity, and you can really feel the downforce building up in the wheel weight as the speed builds and the scenery is pushed past your windows at an ever accelerating rate. As far as Assetto Corsa is concerned, I'd argue that this is hands-down the most difficult car to drive. The power delivery is so immense at the stock boost setting on a green track that it becomes a serious handful, and when the boost is cranked up it becomes pretty much undriveable. Get it right though, and it's more rewarding than anything else I've ever experienced in any consumer simulator. As has been the case with all of the Dream DLC cars, Kunos have pretty much nailed the sounds of this car. The internals are incredibly close to the real version as you can almost feel the monster in the rear shoving you down the road. The externals are top notch as well, but I think the real one sounds a little different, but this is a minor detractor as it still sounds incredible, demonic almost, shouting at you as you heel and toe down the gears going into its next tarmac meal. As far as drawbacks go, I've noticed the wheels don't seem to rotate as quickly as the car is travelling, which means that the motion blur of the sidewalls looks a little strange, however, this has been largely rectified in the latest patch. The C9 then has been wonderfully replicated and is truly rewarding to drive so long as you can spend enough time trying to master it. 4 out of 5 stars. Keep fresh pairs of underwear on hand at all times.