I'm really quite impressed by this kit, and it attaches easily to the Bumblee mould as there is a small hole in Bumblebee that you insert the jetpack/copter to. Don't cut it thinking it's a sprue though!
I found my helicopter blades spin easily, but they tend to go together rather than remaining 180 degrees. I think its going to be easy to fix up with some nail polish, or failing that with a dollop of superglue. It's really an awesome accessory