I'm not 100% sure...but I think that the scooters they use in the movie above are honda sfx scooters.
50cc 2 stroke-scooters are the best to stunt on in my opinion
Offcourse its easier to lift the frontwheel of the ground with 70cc or 100cc but its way harder to control when you go for advanced tricks. If you want to do circle wheelies for example, you need low speeds to go in a circle.... with 70 cc most of the times you have a way higher speed while wheeling and controlling the trottle is harder than on a 50cc. Besides...70cc scooters wil break way earlier than 50cc scooters . 2 stroke scooters are built for 50cc cilinders...
but that is my opinion
Hope it will help you