The length of the film was limited by the short capacity of the reel, and filmed from a gyro-stabilised camera mounted on the bumper of a Mercedes-Benz 450SEL 6.9.[2] This model, which could reach a top speed of 235 km/h (146 mph), was only available with a 3-speed automatic transmission. Yet, one can hear gear changes up into 5th, as well as heel-and-toe down-shifting with a high-revving engine indicating speeds of well over 200 km/h. Calculations made by several independent groups showed that the car never exceeded 140 km/h (85 mph)[3], while another[4] estimated that the car had peaked at 220 km/h (136.7 mph). Lelouch himself claimed that the top speed achieved was over 200 km/h, somewhere between 230 km/h and 240 km/h.[5]It is suggested that the sound was dubbed with the noise of Lelouch's 275GTB, which has a corresponding number of gears and a similar engine note.