My instant answer is NAFF .... you need carbon and more carbon, but guess i would say that as I have the odd acre or 2 on my bike already
But, being objective .... they look like cheap plastic and the clear viewing area will only look that nice when brand new with brand new belts. The minute you run the engine the viewing area will get covered in dust and crap from the belts. Can you imagine how frustrated you would be with a nice shiny bike (even yellow) and a nice shiny viewing window that showed a dirty, dusty part of the engine.