There were some earlier test runs where they simply ran out of track without ever reaching a top speed with this car (265 mph I think it was, in that run). I'm glad they found a longer track. Watching the video, I don't know that this was the "top speed" necessarily, as he seemed to hit 270 and let right off the throttle. Perhaps they ran out of track again? Or decided to cut it at 270? Or, maybe that really is the "top speed" of the car.
Pretty amazing. I think they're $1mil, last I'd looked into them.