As far as i'm concerned they are pretty much the same power wise, its just that the v-force 3 is all clipped together and the 2s are all held together with screws, they did this because the 2s start sripping the holes once you have changed the petals a few times if you are heavy handed on the screwdriver and obviously the screw ends up in your engine but no way that can happen on the 3s.
yes thats right, you can adjust the clamp on the outer petals so they open easier for more bottom end or harder for more top end