I found a video for the reed valve comparements:
NSR tests boites à clapets et clapets (+diffuseur) Italkit, HRC, origine, Boyesen, Technium
https://lirycm.wixsite.com/nsr125/banc de puissance,NSR tests boites à clapets et clapets (+diffuseur) Italkit, HRC, origine, Boyesen, TechniumAVSmoto.fr Cod...
www.youtube.com
Very intresting, if intrest for this topik I recomend view.
The boysen and Italkit not so good (i think so). Original Honda or Technum Carbon is the best based on the test.