Nice addition to the lego range. You might find your kids need some help assembling but will probably find they need no help at all in their demolishon derby. My kids love them - stamping down on the foot pump to send them shooting across the room. Although bits may fly off in the crashes they're easily reassembled. Just as well lego is durable stuff. Just don't vacuum the floor after play until you've reassembled them completely! One isn't enough, you'll need at least two, after all, ahem, the kids need someone to race with...