I believe Adrian Newey (RedBull F1's aerodynamicist, engineer, designer, and chief technical officer) described the car as more of a "thought exercise". "What could we do in F1 if we weren't constrained by the rules? What would the limits be?" - that was his basic premise. Find out what the car would be capable of. It doesn't defy physics; it obeys them. It's a *feasible* idea, if there were anyone capable of really driving it, or courses safe enough for it. Courses are designed around the idea of 200-mph cars, for the most part, with gravel traps and runoff areas designed to slow down a car leaving the track at top speed. When the top speed is more like 350mph, that becomes an order of magnitude harder to do.
There is no real, actual, running version of the X1/X2010/X2011. There is a body mockup, but that's about it. Everything else that exists about the car is only digital bits and bytes...
From an article at the time GT5 was coming out:
"We all know Red Bull's technical director Adrian Newey can design incredible fast cars, but the Brit has really outdone himself with his latest contraption, the Red Bull Technology's top-secret X1 Prototype. According to a report from the GMM news agency, the aforementioned prototype lapped the Suzuka racetrack 20 seconds faster than an actual F1 car.
The X1 Prototype was driven virtually by Sebastian Vettel and was created by Newey for the new PlayStation game Gran Turismo 5, due to be released in November this year. With total freedom to design a racing animal not bound by any technical regulations, the Red Bull technical lived up to his name and created the fastest car of Gran Turismo 5.
“We all have a dream about pushing the boundaries, where the performance of the car and the experience of the driver take precedence over the rules,” said Newey about his latest project..."
http://www.autoevolution.com/news/adrian-newey-designs-x1-prototype-for-gran-turismo-5-24531.html
The car was driven *virtually*. As in, not for real, but only in the game.