With modern cars having ventilated disc brakes and high gear ratios (2nd gear = 60mph and so on) there is not such a need to engage low gears going down hill. Such actions only need to be reserved for driving large vehicles fully laiden down long hills.
I do not believe coasting in neutral is dangerous. Provided you do not switch the engine off, you have power assistance to the steering and brakes. This is only a hypothesis but could your braking performance be improved in neutral? - e.g. you are only braking against the momentum of the vehicle, not the momentum of the vehicle and the engine resistance.
The average car will not increase its speed much in one second of full throttle acceleration especially if you are cruising in a high gear. It takes much less than this to put the car into gear if you're in neutral.
Having said this, and despite doing it myself (I started a separate thread in the 2nd gen
MCS forum), coasting in neutral is quite a drastic action to save fuel consumption. Though I employed it at the weekend and managed a reported 57mpg in a R56
MCS over 120 miles.
