Had the pleasure of seeing this in person at Bimmerfest and for a couple seconds I didn't even notice the supercharger until I glanced back at it a couple of times. It could easily pass as a stock manifold to the untrained eye.
Soorena... you are correct! This is a roots type supercharger
The guys from Harrop were really knowledgeable and I'm definitely looking forward to seeing more positive feedback once this kit is released.