Bravo to JLC, every year they bring their technical savvy to horology world,
I think this piece is much better than Gyro, as Sphero dont have ball cage outside the tourbi,
and as for the hairspring, as Dje said, it is like a d*mn hearbeat, simply mesmerising,
apart from the staggering price (actually reasonable for this kind of complication),
It would be a dream for me
everything is just fine 
thanks Nicolas for wonderful review,
ES