E60 on 53plate recently when i drive it around 60mph up untill 80mph my car shakes?

its not a speed warning as they would have just put an annoying alarm in the cab which would be much cheaper than designing a device to shake the car at 70 mph and don't forget they can drive at greater speeds on autobahn i think you will find that its a simple case of poor wheel balancing or alignment have you had the rear wheels tracked as most people don't realise that they can be out of alignment too especially if they take them up and down curbs regularly i doubt if its a transmission or prop shaft problem as these will result in a humming and the shake would gradually get worse and not just appear and then go away