Does your friend notice a difference doing it that way and just with braking and sport + in D? I never heard of anyone doing that way. I've done it braking and with RPM at 2k in D + sport mode, sometimes the tires will spin, just a bit though. I know your not suppose to do a nutral drop with autos cause I've heard a lot of guy messing up their trans that way.

Actually Supercharging a car has nothing to do with transmissions, it will still be a bit slower 0.6 - 1 sec slower but thats about it.